Thermoset adhesive having susceptor particles therein

ABSTRACT

Multilayered film and film based assembly which are environmentally-compatible, and which exhibit one or more desirable characteristics of polyvinyl chloride (PVC) film and film based assemblies, such as clarity, flexibility and toughness, but without the environmental and health hazards associated with PVC materials, are provided. Also provided is a method of preparing such film and film based assembly.

This application is a division of application Ser. No. 08/103,082 filedAug. 6, 1993, now abandoned.

FIELD OF THE INVENTION

This invention relates to multilayered films and film based assemblies,such as medical pump cassettes, which are suitable to replaceconventional polyvinyl chloride (PVC) films and assemblies, but withoutthe environmental and health hazards associated with PVC materials.Further, this invention also relates to medical devices such asintravenous fluid administration sets made with PVC-free materials,which may include such film based assemblies along with othercomponents.

BACKGROUND OF THE INVENTION

Polyvinyl chloride (PVC) based films and film based assemblies are usedin numerous medical products. However, PVC is viewed as hazardous toboth the environment and to personal health. Incineration of PVC resultsin the release of hydrochloric acid (HCl), and PVC is viewed as a majorcontributor to HCl in incinerator flue gases. Also, PVC is suspected ofcontributing to polychlorinated dibenzodioxin and furan toxins formedduring incineration. Levels of these toxins are up to three timesgreater in medical infectious waste as compared to municipal wastestreams. In addition to incineration concerns, exposure todi-2-ethylhexyl phthalate (DEHP), a common plasticizer used with PVC,may present a number of health related concerns, including reduced bloodplatelet efficacy and potential links to liver cancer.

Despite these concerns, PVC-based films and film based assemblies,continue to be the material of choice in scientific and medicalapplications. See, e.g., Encyclopedia of Polymer-Science and Technology,Vol. 17, pg. 50 (1989). The continued use of PVC materials is due, atleast in part, to PVC's attractive qualities, including flexibility;toughness; resistance to UV light, solvents, cuts, scratches, and acids;clarity or opaqueness as required; and low cost. In addition, PVC'scharacteristics can be modified through the addition of variousadditives, such as plasticizers, colorants, and the like. For example,U.S. Pat. No. 4,298,714 discloses a modified PVC material with reducedhydrophilicity due to the addition of various thiol-group compounds tothe PVC backbone.

Other thermoplastic polymers have been used to form single-layer filmsand film based assemblies, For example, low-density polyethylene, highdensity polyethylene, polypropylene, ethylene vinyl acetate, andpolybutylene have all been used to form single-layer films and filmbased assemblies. Encyclopedia of Polymer Science and Technology, ibid.,pp. 50-51. Further, films developed for replacement of PVC are oftenmade of polyolefins. Polyolefins have low surface energies and are oftendifficult to bond with conventional adhesives or solvents. Consequently,none of these polymer materials has been successfully used to providefilms and film based assemblies with the advantageous characteristicsneeded to serve as environmentally compatible replacements for PVC-basedmaterials.

The problem is particularly acute with respect to tubing assemblies withcassettes used in connection with infusion pumps for metering IV fluidsto a living patient. Cassettes, for example as taught in U.S. Pat.4,236,880 to Archibald, must be highly flexible so as to deform in themanner of a rolling diaphragm when pressed by a pumping piston. Theymust additionally be tough enough to withstand repeated deformation forextended periods of time: 72 continuous hours is a typical institutionalrequirement among U.S. hospitals. Such cassettes are prepared bycompression blow molding such that the material must be able to form asecure heat bond during the fabrication.

In addition to continued environmental incompatibility, these films andfilm based assemblies tend to delaminate during continuous usage. Toavoid delamination problems, U.S. Pat. No. 3,561,493 provides amultilayered film in which the inside and outside layers are weldedtogether by a precompounded layer of the two different polymers.However, chlorine-containing polymers, such as PVC, are still consideredbest for use in such films and film based assemblies.

To date, no films and film based assemblies exist which provide theadvantageous characteristics of PVC materials, and yet areenvironmentally compatible upon disposal.

Therefore, there is a need for films and film based assemblies that canbe utilized in a wide range of both medical and nonmedical products, andthat can serve as replacements for PVC-based materials. There is a needfor elements of medical devices such as IV infusion therapy sets whichare environmentally compatible, and yet capable of satisfying thechallenging requirements. Specifically, there is a need for PVCreplacement cassettes, IV sets and medical films which are extremelyflexible, yet tough enough to endure their intended use. They must becapable of being heat bonded, must be visually transparent, as well assolvent and UV light resistant, and capable of being made for arelatively low cost.

SUMMARY OF THE INVENTION

The present invention is directed to a multilayered film, a film basedmedical device assembly such as a medical cassette and methods forformation of the film and the film based medical device assembly.

The film is the building block component for the medical deviceassembly. The film has at least a core layer, an outside surface layerand an inside surface layer composed at least of chlorine-freethermoplastic polymers. The film has the capability of bonding to itselfunder heat conditions before the film core can distort substantially.Further the film is capable of being expanded at least in part underheat and pressure without failure of film integrity, flexibility andresilience. In preferred embodiments, an optional divider layer orlayers is present within the core layer. In other embodiments, the corelayer can also act as one of the surface layers.

The core layer is composed of at least one chlorine-free, firstthermoplastic polymer, or a mixture of such first thermoplasticpolymers, or a mixture of such first thermoplastic polymers with othersubstances and polymers. The outside surface layer is composed of atleast one chlorine-free, second thermoplastic polymer, or a mixture ofsuch second thermoplastic polymers, or a mixture of such secondthermoplastic polymers with other substances and polymers. The insidesurface layer is composed of at least one chlorine-free thirdthermoplastic polymer, or a mixture of such third thermoplasticpolymers, or a mixture of such third thermoplastic polymers with othersubstances or polymers. The additional internal layers may mostconveniently be composed at least of one of the first, second and thirdthermoplastic polymers or a mixture of such thermoplastic polymers aloneor with other substances and polymers. Also such additional internallayers may be, but preferably are not, composed of halogen containingpolymers such as polyvinyl chloride or polyfluorocarbons.

The first thermoplastic polymer has a flexibility that mimics or isgreater than that of the polyvinyl chloride used to make medical gradefilm. In particular, it has a flexibility substantially needed toachieve film functions ranging from a capability to flex and recover, toa capability to be expanded without failure or deformity. Morespecifically, the first thermoplastic polymer has a flexibility that ismeasured as a Young's modulus that substantially mimics or is less thanthat of polyvinyl chloride film used for medical applications.Preferably, the first thermoplastic polymer Young's modulus ranges fromabout 10 to about 60 MPa (megaPascals), more preferably from about 10 toabout 50 MPa especially preferably from about 15 to about 40 MPa.

The second thermoplastic polymer is tough and has an abrasion resistancethat substantially mimics that of PVC used for medical film. It has aYoung's modulus up to about ten times the Young's modulus of the firstthermoplastic polymer. Preferably this ratio is up to a maximum of aboutseven times, more preferably, in a range of from about equal to, up toabout three times, the Young's modulus of the first thermoplasticpolymer. Especially preferably, this ratio is greater than, up to aboutthree times the Young's modulus of the first thermoplastic polymer.Preferably, the Young's modulus of embodiments of the secondthermoplastic polymer ranges from about 15 to about 300 MPa, morepreferably from about 15 to 150 MPa.

The third thermoplastic polymer is able to form a strong heat seal toitself or like materials. It contains essentially no medically harmfulsubstances that can be extracted or leached into an aqueous or organicbased fluid stream and it will not absorb medications. It is preferredthat the third thermoplastic polymer is capable of adding to the tensilestrength of the composite film. It is also preferred that the thirdthermoplastic polymer has a Young's modulus within the general andpreferred ranges given above for the second thermoplastic polymer.

Any thermoplastic polymer having the appropriate characteristicsdescribed above is appropriate for use as the first, second or thirdthermoplastic polymer. Generally, the first, second and thirdthermoplastic polymers have backbones of any configuration and chemicalstructure that will maintain the foregoing characteristics andthermoplasticity during multilayered film based assembly formation.Backbone configurations include but are not limited to linear, random,cross-linked, grafted, block, crystalline-amorphous domains,pseudo-cross-linked and ionomeric. Backbone chemical structures includepolyolefin, polyester, polyurethane, while specific polyolefins includepolyethylene/polyvinyl alcohol, polyethylene/polyvinyl acetate,polyacrylates, polymethacrylates, and polyvinyl acetates. Preferredthermoplastic polymers include the polymers of olefin monomers orcopolymers of olefin monomers and substituted olefin monomers.Especially preferred olefin monomers include C2 to C4 mono-unsaturatedalkenes and especially preferred substituted olefin monomers include C4to C14 mono-unsaturated alkenes, C8 to C14 aryl alkenes, and C2 to C6mono-unsaturated alkenes having moieties selected from the groupconsisting of acetoxy, carboxy, oxyalkanoyl, and alkoxycarbonyl of 1 to6 carbons in the alkoxy group. The use of such a thermoplastic polymeras a first, second or third thermoplastic polymer depends but is notlimited to the percent of substituted olefin monomer present in thepolymer, the degree of regular molecular orientation achieved by thepolymer, the degree of cross-linking, pseudo-cross-linking orionomericity present, the backbone configurations mentioned above, thedegree of the three dimensional rotation allowed by the chemicalbackbone structure, the degree of crystallinity and the nature of themonomer constituting the majority of the polymerized unit in thepolymer.

The first thermoplastic polymer is flexible and soft. The secondthermoplastic polymer is tough. The third thermoplastic polymer ispreferably but not necessarily tough. The first thermoplastic polymerprovides a film core with conformability and elasticity. The secondthermoplastic polymer provides an outside surface layer with abrasionprotection and non-stick release. The third thermoplastic polymerprovides an inside surface layer with tensile strength and heat sealingability. The thermoplastic polymers for the optional divider layerprovide dimensional stability and tensile strength. In cooperation, thesurface and core layers provide a multilayer film and film basedassembly that are approximately as flexible, elastic, resilient andstrong as, and in preferred embodiments exceed those characteristics of,PVC films and film based assemblies. The multilayer film is also asdurable and scratch/abrasion resistant as PVC.

The multilayer film can have several configurations including threelayer, five layer and megamulti (more than five) layer configurations.In all configurations, the outside surface, inside surface and dividerlayers are united or contiguously attached to the core layer. In thethree layer configuration, the core layer is sandwiched between insideand outside surface layers. In the preferred five layer configuration,the inside, outside and core layers are constructed as in the threelayer configuration. In addition, the divider layer is placed inapproximately the middle of the core layer so as to divide the corelayer into two parts. The divider layer in this configuration acts tofurther stabilize the core layer during formation of an assembly from afilm.

In preferred embodiments, the core layer will be composed of a copolymerof an olefin and a substituted olefin and in particularly preferredembodiments, the copolymer can be an ethylene-vinyl acetate copolymer,an ethylene-butene copolymer, an ethylene-methyl acrylate copolymer, avery low modulus ionomer, and combinations thereof.

In preferred embodiments, the outside surface layer will be a non-stickor release olefin copolymer. A copolymer of ethylene and 1-octene or ofethylene and methyl acrylate is considered particularly suitable.

In preferred embodiments, the inside surface layer will be composed ofan ionomeric copolymer. A copolymer of ethylene and methacrylicacid-metal cation salt is considered particularly suitable.

The film based assembly according to the invention is usually formedfrom two sheets of the multilayered film. The assembly is constructed tofunction in the capacity of, and to have characteristics similar tothose of, a medical device made of a PVC composition. In a preferredembodiment, the film based assembly is a medical fluid bag, a flexibleplastic drug container, or a medical pump cassette with molded-in fluidchannels and pumping bubbles. The outside surface layer of the filmbased assembly provides a tough, protective coating for the assemblywhile the core layer provides the needed elasticity and flexibility. Theinside surface layer provides not only toughness but also isparticularly adapted for heat bonding. The optional divider layerprovides additional dimensional stability and high precision formationduring heat molding and sealing.

The invention is also directed to a method of forming a film basedassembly. Such a method involves several steps, including forming a filmas a sheet material by coextruding the first, second and third andoptional divider thermoplastic polymers as contiguous united layers.

In a second step, the molded portion of the assembly is produced bymolding a plurality of the sheets in a compression blow mold having atleast two mold halves with at least one having internal cavities. In apreferred embodiment, two sheets of the film are placed between the moldhalves with their outside surface layers facing the mold halves andtheir inside surface layers positioned to touch each other when the moldis closed. The molded portion of the assembly is molded by closing themold halves and applying pressure and heat to the sheets while applyinggas pressure to the portions of the sheets within the internal cavities.

The molded portion of the assembly is then optionally bonded to itsconnective or other preformed components, which in many cases will bepolymeric tubing. In preferred embodiments, the polymeric tubing willalso be fabricated from chlorine-free polymers. This bonding may be doneby appropriate adhesives, or may advantageously be performed by applyinga mixture of a polymeric binder and susceptor particles to theconnective components, placing the connective components and the moldedportion of the assembly in contact with each other, and subjecting thecombination to electromagnetic radiation. The susceptor particles thenabsorb the electromagnetic radiation and generate heat. This heat meltsthe polymeric binder material and bonds the assembly together.

When adhesive bonding is performed, some otherwise appropriate adhesiveshave little green strength., and in such cases, susceptor particles maybe mixed with the adhesive, and the adhesive exposed to electromagneticradiation to speed the cure and to enhance the green strength.

The invention is also directed to a method for bonding together at leastone tube and at least one plastic fluid transporting component. Themethod includes the steps of coating at least a portion of one of thetube and the plastic fluid transporting component (article) with thepolymeric binder with susceptor particles wherein that portion is anarea of the article to be bonded to the other article. The areas of thearticles to be bonded together are contacted. Those contacted areas areirradiated with electromagnetic radiation. The susceptor particlesabsorb the radiation and cause local melting of the adhesive and/orplastic material and hence bonding or sealing together. The susceptorparticles can be ferrite powders, metal powders, carbon black, graphitepowders, amorphous metal powders or coated particles with optionalthermoset polymers. The amorphous metal powders are described incopending and coassigned U.S. patent application Ser. No. 07/800,632.The coated particles can be particles, such as glass fibers, glassbubbles, or mica flakes, coated with a thin, continuous metallic film.Such coated particles are described in copending and coassigned U.S.patent application Ser. No. 07/668,974. Most kinds of thermoplasticpolymer can be bonded by this method. Preferably, the method employs athermoplastic polymer as described in the present application.

The invention is also directed to a method for bonding two components.The method includes the steps of coating at least a portion of one orboth of the components with a thermoset adhesive mixed with susceptorparticles wherein that portion is an area of the component to be bondedto the other component. The areas of the components to be bondedtogether are contacted. Those contacted areas are irradiated withelectromagnetic radiation. The susceptor particles absorb the radiationand enhance green strength of the adhesive. Conveniently, the componentsmay be a tube and a fluid transporting part.

The invention is also directed to a composition of matter, comprising amixture of a thermoset adhesive and susceptor particles. Convenientlythe thermoset adhesive is an epoxy adhesive, and the susceptor particlesare for example particles coated with ferromagnetic or ferromagneticmaterial, particles coated with conductive material, and ferromagneticamorphous powders. The volume loading of the susceptor particles in themixture is preferably between about 1% and about 65%, and morepreferably between about 1% and about 30%.

The multilayered film and film based medical device assembly of thepresent invention are flexible, tough, abrasion resistant and heatformable. They do not release harmful chemicals such as hydrogenchloride to the atmosphere when they are burned or otherwise degraded.The multilayered film and film based assembly of the present inventionare also safe and effective for use in medical applications. At leastthe surface layers of the film and assembly contain no plasticizer orother leachable or extrudable ingredient which could contaminatepharmaceutical fluids. In particular, at least the surface layerscontain no phthalate or citrate esters or other plasticizers oradditives which are capable of leaching into pharmaceutical fluids. Themultilayered film and film based assembly also have an ability to avoidabsorption of solvents, drugs, pharmaceutical agents and other materialswhich come in contact with the film and film based assembly. Thischaracteristic is especially desirable when the film and film basedassembly are used as medical products. In this application, the film andfilm based assembly display minimal or no absorption of drug,pharmaceutical carrier or other pharmaceutical liquid. Optionally, thefilm and film based assembly layers can be composed of thermoplasticpolymers which will make the layers resistant to acid, solvent, UVlight, and will render the film and film based assembly clear or opaqueor colored.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a first embodiment of a multilayeredfilm assembly having outside and inside surface layers and a core layer.

FIG. 2 is a cross-sectional view of a second embodiment of amultilayered film having outside and inside surface layers, a core layerof two parts and a divider layer between the two parts of the corelayer.

FIGS. 3A and 3B are top and left side views respectively of anembodiment of a film based assembly according to the invention. Theembodiment is a medical pump cassette.

FIG. 4 is a medical IV bag compression mold formed from two sheet filmsaccording to the present invention.

FIG. 5 is a complete medical IV tubing assembly.

FIG. 6 is a view of a cassette forming device.

DETAILED DESCRIPTION OF THE INVENTION

The multilayered film and film based assembly of the present inventionpossess physical characteristics much like those of polyvinyl chloride(PVC) film and film based assemblies. In addition, the multilayered filmand film based assembly are environmentally safe and avoid medical,pharmaceutical and health-related drawbacks of PVC. The polymeric layersof the multilayered film and film based assembly are made of a corelayer of at least one soft, flexible thermoplastic polymer and surfacelayers of at least one tough, abrasion-resistant thermoplastic polymer.These layers contribute a composite of their characteristics to themultilayered film and film based assembly. Moreover, the core layer ispreferably at least slightly larger in thickness than either of the twosurface layers. In this fashion the flexibility characteristics of thecore layer dominate the composite. At least the surface layers andpreferably all layers are free of any additives, plasticizers or othercomponents which could be extracted or could exude or leach into fluidsin contact with the layers.

Definitions

Certain terms and phrases are used to describe the film and film basedassembly. Generally, these terms and phrases have the ordinarydefinitions understood by those of skill in the art. Several, however,have particular meanings as given below.

The term "Young's modulus" means the amount of force per unit volume ofmaterial needed to elongate the material a unit distance after thestress has been initiated and before the curve of stress againstelongation becomes non-linear. The Young's modulus is measured inmegaPascals (MPa).

The term "cassette" means a device generally formed of a multiple numberof overlaid plastic sheets. The cassette possesses internal passagesand/or chambers and/or bubbles suitable for conducting fluids. Thecassette may be a pumping cassette suitable for metering fluids inconnection with an infusion pump.

The term "plastic fluid transporting component" means a component formedat least partially of a polymer and having a lumen for conducting fluid.Non-limiting examples include cassettes, tubing, luer locks, injectionsites, bag spikes, filters, check valves, and drip chambers.

The term "environmentally compatible" means capable of being handled ortreated by a usual method for disposal of medical devices without therelease of harmful, noxious or toxic substances to the environment.Usual methods for such disposal include but are not limited to burningand burying.

Physical Characteristics

Toughness and resistance toward abrasion and cuts as well as highflexibility are physical characteristics that are essential for medicalfilm and film based medical device assemblies. The medical film and filmbased assembly must survive the long term abrasion forces of suchmedical instruments as infusion pumps and friction fittings. They alsomust have high flexibility and elasticity so that internal fluidchannels and pumping bubbles will maintain their integrity and operateunder repetitive flex conditions.

Tough, abrasion resistant thermoplastic polymers typically are notflexible enough for use in medical films and film based assemblies.Highly flexible thermoplastic polymers typically are not tough enoughfor use in medical films and film based assemblies. Consequently, untilthe present invention, a non-PVC film had not been developed whichexhibited a toughness, abrasion resistance, flexibility, durability,non-stick release, flexibility and expansion without failure.

According to the present invention, a multilayered film of a flexiblechlorine-free thermoplastic polymer core layer and tough, thermoplasticpolymer outside and inside surface layers, and a film based medicaldevice assembly of at least two overlapping, heat and compression joinedfilms have been made which have flexibility, durability, elasticity,strength, toughness, abrasion resistance, non-stick release andexpansion without failure. The multilayered film and film based assemblyincorporate at least the following parameters a through e and preferablythe remaining parameters as well.

a. The first thermoplastic polymer has a flexibility mimicking orgreater than that of polyvinyl chloride medical film. More specifically,the first thermoplastic polymer has a flexibility sufficient to enablethe film to endure mechanical pump action on an expanded bubble formedfrom the film; i.e. flexing from a fluid filled, fully expanded bubble,down to a completely flat, unfilled condition where the pumping occursrepeatedly between two hard surfaces. Preferably the flexibility of thefirst thermoplastic polymer is measured by its Young's modulus which inespecially preferred embodiments is within a range of about 15 to about40 MPa (megaPascals). Examples of PVC medical films acting as referencepoints for the flexibility mimicked by the first thermoplastic polymerinclude but are not limited to medical and general purpose PVC filmssuch as PVC film plasticized with 40% diethylhexyl phthalatemanufactured by O'Sullivan Corporation of Newton Upper Falls, Mass. Alsoillustrative of PVC properties in medical applications include "Nalgene"brand USP VI grade tubing, commercially available from Nalge Co. ofRochester, N.Y., and "Tygon" brand tubing commercially available fromNorton Performance Plastics of Wayne, N.J. The Young's modulus of thePVC's used in such films range from about 17 MPa to about 40 MPa.

b. The second thermoplastic polymer and preferably but not necessarilythe third thermoplastic polymer have a Young's modulus that is not morethan about ten times, preferably from about equal to, up to no greaterthan, about ten times, more preferably within a range of greater than,up to about ten times, the Young's modulus of the first thermoplasticpolymer. Especially preferably, the Young's modulus of the secondthermoplastic polymer ranges up to no more than about seven times, mostpreferably up to no more than about three times, the Young's modulus ofthe first thermoplastic polymer. Preferred embodiments have a Young'smodulus of the second thermoplastic polymer within a range of from about15 to 300 MPa, more preferably within a range of from about 15 to 150MPa.

c. The core of the film provides at least a slight majority of the filmthickness relative to any other single layer. More specifically, thethickness ratio of the film layers incorporating first thermoplasticpolymer to the film layers incorporating second, third and additionalthermoplastic polymer is about 1:1 to about 10:1, preferably from about1:1 to about 5:1. This parameter allows the flexibility of the film coreto dominate the composite flexibility characteristics of themultilayered film.

d. The multilayered film through the action of the third thermoplasticpolymer and the third thermoplastic polymer itself have a capacity toself-heat seal before the core and the outside surface layer becomeplastic or otherwise deform under heat. Further, the film is capable ofbeing expanded through pressure molding to form expanded structureswithin the film such as pockets which can repeatedly be compressed overa long duration without failure. The expansion also is achieved withoutfailure of film integrity, flexibility and resilience.

e. The outside surface layer of the film and in preferred embodiments,the multilayered film based assembly itself preferably exhibit a hotsurface release and an abrasion resistance that mimic or are greaterthan that of polyvinyl chloride medical film. More specifically, theoutside surface layer of the film, and preferably, the multilayered filmitself, exhibits an outside surface abrasion resistance having anabrasive index range of at least about 100 as measured by ASTM testD1630-83, the standard test method for rubber property--abrasionresistance.

f. In addition to the flexibility of the first thermoplastic polymer andthe core of the film, the multilayered film itself preferably exhibits aflexibility that mimics or is greater than that of polyvinyl chloridemedical film. More preferably, the multilayered film has a Young'smodulus within a range of about 15 to about 60 MPa.

g. The multilayered film preferably exhibits essentially completeresiliency in an expanded form and essentially no expanded wall failureduring an endurance test as a rolling diaphragm of at least 10,000cycles through expansion and compression between a completely filledcondition and a completely collapsed condition. The wall should returnto its original state to show essentially complete resiliency. It shouldnot crack or exhibit signs of stress weakening to show essentially nowall failure.

The multilayered film and film based assembly are capable of bonding tothemselves and to other plastics through the use of adhesive bonding,radio frequency welding, microwave welding and thermal welding. Themultilayered film and film based assembly are sterilizable through gammairradiation and ethylene oxide. They preferably do not degrade undersuch sterilizing conditions. The multilayered film and film basedassembly resist oxidative and ultraviolet degradation such that in apreferred embodiment, they have a significantly long shelf life and donot turn yellow or age like polyvinyl chloride.

Core Layer Thermoplastic Polymer

The first thermoplastic polymer is used to form the core layer of thefilm. It includes any soft conformable thermoplastic polymer having thecharacteristics, flexibility and preferably the Young's modulus asdescribed above. Preferred thermoplastics include polymers of a C2 to C4mono-unsaturated alkene, copolymers of a majority of a C2 to C4mono-unsaturated alkene with a minority of a substituted olefin monomersuch as C4 to C14 mono-unsaturated alkene or a C8 to C14 aryl alkene,and copolymers of a majority of a C2 to C4 mono-unsaturated alkene witha minority of a substituted C2 to C6 mono-unsaturated alkene having asubstituent such as C1 to C6 alkoxy carbonyl, carboxylic acid,carboxamide and carboxylic ester groups. Examples include copolymers ofolefins such as ethylene and propylene with substituted olefins such asvinyl acetate (EVA or PVA), N-methyl acrylamide (EAM or PAM), acrylicacid (EAA or PAA), methacrylic acid (EMA and PMA), EMA or PMA ionomers(EMAZ, EMAS or PHAZ with metals such as zinc or sodium) and acrylate andmethacrylic esters having C1 to C6 alkyl groups. In the case of EVA andPVA, the acetate can be partially or wholly hydrolyzed to yieldpoly(vinyl alcohol) (PEA). Examples as well include ethylene orpropylene copolymers of all hydrocarbon substituted olefins such asethylene or propylene and styrene (ES or PS), ethylene or propylene andbutene (EB or PB) and ethylene or propylene and octene (EO or PO).Particular examples include copolymers of ethylene and vinyl acetate,ethylene and butene, ethylene and n-butyl acrylate, and ethylene andethyl acrylate.

Generally, as the amount of substituted olefin monomer or alkyl or arylolefin monomer is increased in such an olefin copolymer, the Young'smodulus of the copolymer will decrease. Consequently, the ratio ofmajority olefin monomer to minority substituted olefin monomer in thecopolymer will be selected so that the copolymer will have theappropriate Young's modulus as described above. Preferably, this amountis from about 2% to about 50%, especially preferably about 10% to about40% on a molar basis.

Under certain circumstances, the first thermoplastic polymer can alsohave characteristics suitable for one of the surface layers. Filmconstructions of this nature will at least be tri/bilayer film where thecore layer is also acting as one of the surface layers.

Outside and Inside Surface Layer Thermoplastic Polymers

The second and third thermoplastic polymers include any tough, abrasionresistant thermoplastic polymer having the characteristics and the highYoung's modulus as described above (especially, the importantdistinctive characteristics of non-stick release and self-sealing,respectively). In addition to linear backbone structures providing ahigh order of intermolecular orientation, other desirable backbonestructures for the second and third thermoplastic polymers include thosehaving: cross-linking, backbone branching, grafting, ionomeric linking,a combination of crystalline and amorphous domains, hydrogen bonding andmolecular orientation such as through a backbone structure thatrestricts the degrees of three dimensional movement of the backbone(hereinafter, Intermolecular Linking). Generally the second and thirdthermoplastic polymers have the same characteristics but are notnecessarily of the same chemical structure. Preferably, the second andthird thermoplastic polymers include polyolefins, cross-linkedpolyolefins, olefin-substituted olefin copolymers as well aspolyurethanes, polyethers, and polyesters. The olefinic monomers usedalone or in combination to form the polyolefins can be selected fromaliphatic and aromatic olefins of two to fourteen carbons such asethylene, propylene, butene, octene and styrene. Preferred polymers andcopolymers of such olefins include polyethylene, polypropylene,copolymers of ethylene and butene (EB) and copolymers of ethylene andstyrene (ES). In copolymers of olefins, the minor olefin monomer (C4 toC14) preferably is present in a range of from about 1% to about 20% on amolar basis.

When a copolymer of a C2 to C4 olefin and a substituted olefin is usedas a second or third thermoplastic polymer, the substituted olefinicmonomers can also be selected from C2 to C4 mono-unsaturated olefinswith such substituents as acetoxy, oxyalkanoyl, carboxyl, carboxamidoand other similar polar groups. Examples include acrylic acid,methacrylic acid, acrylamide and similar hydrogen bonding orcross-linkable olefins.

The optional Intermolecular Linking in the second and thirdthermoplastic polymers will be low enough to preserve the thermoplasticcharacter of the polymer but sufficient to provide the degree ofabrasion resistance and toughness meeting the Young's modulusrequirement described above. Preferably the Intermolecular Linking is inthe range of from about 0.1% to about 10% especially preferably about0.2 to about 5% on a molar basis. Moreover, as indicated above, thethermoplastic olefin copolymers are selected according to the guidelinesaffecting the Young's modulus. Preferred copolymers include a majorityof C2 to C4 olefin monomer and a minority of polar, aprotic substitutedolefin monomer. Preferably, the amount of minority monomer present isfrom about 2% to about 40%, preferably about 5% to about 30% on a molarbasis.

Preferred Polymers for Core and Surface Layers

In preferred embodiments, the first, second and third chlorine-freethermoplastic polymers are all olefinic polymers. Examples of preferredfirst thermoplastic olefinic polymers include ethylene-vinyl acetatecopolymers (EVA), ethylene-methyl acrylate copolymers (EMAC), ethylenealkyl acrylate copolymers such as ethylene n-butyl acrylate copolymers(EBA), ethylene-butene copolymers (EB), and combinations thereof. Otherexamples include the foregoing blended with ionomers.

Nonlimiting examples of second thermoplastic olefinic polymers includeethylene-octene copolymers (EO) (such as the Attane™ copolymersmanufactured by Dow Chemical Co., Midland, Mich.), EMAC copolymers (suchas are manufactured by Chevron Chemical Corp., of Houston, Tex.).

Nonlimiting examples of the third thermoplastic olefinic polymersinclude ionomeric ethylene-methacrylic acid copolymer with zinc (EMAZ)or sodium (EMAS) doping, such as the Surlyn™ copolymers manufactured bythe DuPont Co., Wilmington, Del.

The first, second and third thermoplastic polymers may also constituteolefin copolymers of the same two monomers but with differing ratios ofthose monomers. That differing ratio changes the modulus value of theresulting copolymer and hence makes the copolymer a first, second andthird thermoplastic polymer. For example, the first, second and thirdthermoplastic polymers can all be obtained from EVA and EBA copolymersby altering the percent by weight content of vinyl acetate (VA) andn-butyl acrylate (n-BA) monomers, respectively, in those EVA and EBAcopolymers. EVA and EBA copolymers with relatively high VA and n-BAcontents provide low Young's modulus materials suitable for use in thecore layer of multilayered film. On the other hand, EVA and EBAcopolymers with relatively low VA and n-BA contents provide high Young'smodulus materials suitable for use in the outside surface layer and theinside surface layer. For example, when an EBA copolymer composes theoutside and inside surface layers, its n-BA content is preferably fromabout 1% to about 20%, more preferably from about 1% to about 15%, andmost preferably from about 2% to about 10% on a molar basis. In anotherexample the core layer of a three layer film is an EVA copolymer with aVA content of from about 20% to about 30% VA, while the outside andinside surface layers are EVA copolymer with a VA content of from about5% to about 10% VA on a molar basis. Alternatively, the outside surfacelayer of that film can be an EVA copolymer with a VA content of fromabout 5% to about 10% VA, while the inside surface layer of that filmcan be an EVA copolymer with a VA content of from about 10% to about 20%percent VA on a molar basis.

Dimensions

The thicknesses of the core and surface layers and of multilayered filmand film based assembly will vary depending upon the intended use, andthus, can readily be selected by those skilled in the art. However, in apreferred embodiment, the outside and inside surface layers aremoderately thin layers covering the core layer. In particular, theincreased hardness and toughness of the outer surface layers, and theheat seal requirements of the inner layer, allow them to be coextrudedas thinner layers than the core. In particular, these layers function toprotect the core from abrasion and pick-up of dirt, serve as a releaselayer (outside surface) to assist in removing a molded assembly from amold, and serve as a self-sealing layer (inside surface). Accordingly,the ratio of the thickness of the two surface layers to the core layeris preferably from about 1:1 to about 1:14, more preferably from about1:2 to about 1:14. For example, when using the preferred EVA, EO, andEMAZ or EMAS copolymers to form a film and film based assembly accordingto the present invention, a core layer is preferably from about 125 μ toabout 350 μ, more preferably from about 200 μ to about 300 μ, and mostpreferably from about 200 μ to about 275 μ thick, while the outside andinside surface layers are each preferably from about 25 μ to about 125μ, more preferably from about 50 μ to about 100 μ.

Thermoplastic Polymer Modulus Measurement

The stiffness/flexibility of a given thermoplastic 30 polymer isconveniently measured and expressed in terms of the Young's modulus, asreported in megaPascals (MPa), for the polymer. A polymer with a lowYoung's modulus (e.g., from about 6 MPa to about 30 MPa) is soft andflexible while a polymer with higher Young's modulus values (e.g., fromabout 25 MPa to about 300 MPa) is relatively stiff and inflexible. Thelow Young's modulus polymers also tend to be more easily cut orphysically abraded and serve as the first thermoplastic polymer.Conversely, the high Young's modulus polymers present a relatively hard,tough (i.e., cut and scratch-resistant) surface and serve as the secondthermoplastic polymers.

The following examples section provides the details for suchmeasurements as applied to multilayered films. The functional andnumeric parameters for stiffness and flexibility of the first, secondand third thermoplastic polymers used in the multilayered films arerelated to, and in preferred embodiments, are indicated by the Young'smodulus of these polymers. Those parameters are given above.

The measurement of Young's modulus was performed using a Material TestSystem (MTS) 880 (MTS Systems Corporation, Eden Prairie, Minn.) with anMTS Sintech Testworks II Application Software Package, version 2.1.Samples of film were prepared for testing by cutting strips 0.5 inch(1.2 cm) wide by 6 inches (15.24 cm) long. These were then inserted intothe gripping jaws of the MTS testing machine, and a rate of elongationof 15.24 cm (6 inches) per minute was set. For each film sample, threereplicates were run. For each replicate the following information wascomputed and averaged:

1. Young's modulus, computed as the maximum slope of the stress/straincurve, using a 3% strain segment length (actually the slope at 0%strain).

2. Load at 50% strain

3. Stress at 50% strain

Since stress/strain characteristics can change over time afterextrusion, measurements are reported after at least one month followingextrusion unless otherwise stated.

Tie Layer and Optional Additives

While it is preferable not to utilize a tie layer or layers in themultilayered film to bond the various layers together, there may bemultilayered constructions in which such layers are desired. When a tielayer is employed, it can be composed of materials which providestructural integrity to the multilayered constructions, withoutsubstantially affecting the other desirable characteristics of themultilayered film, such as flexibility, clarity andenvironmental-compatibility. The selection of the particular tie layermaterial to be utilized in multilayered film according to the presentinvention, from the wide variety of available tie layer materials, issubject to the particular needs and preferences of those skilled in theart. Preferred tie layer polymers include viscoelastic polymers whichhave functionalities that are compatible with and bind to the layers tobe tied, which in the case of preferred embodiments may be copolymers ofmethacrylic acids.

To provide specific additional characteristics to multilayered films ofthe present invention, any one, or all, of the layers can also containconventional non-leachable additives, such as antistatic materials,pigments, dyes, UV absorbers, nucleating agents, quenching agents andthe like. For example, ultraviolet absorbers can be added to one or moreof the layers of the multilayered film for application in IV cassettesused with light-sensitive drugs.

Methods of Preparation

The preferred method of preparing multilayered film and film basedassembly according to the present invention is through coextrusion.Coextrusion is a polymer processing method for bringing diversepolymeric materials together to form a unitary layered structure, suchas film and sheets of the film. This allows for unique combinations ofmaterials, and for structures with multiple functions, such as,toughness, flexibility and environmental compatibility.

Component polymeric materials according to the present invention can becoextruded from the melt state in any shape, according to the intendedend use thereof. The shape and/or thickness of the coextruded layerswill be dependent upon the efficiency of the particular extrusionequipment utilized. Generally, films having a flat continuous sheetconstruction are the preferred coextruded structures. The films can beformed by coextrusion from linear dies and optional hot calendering andby coextrusion from circular dies followed by gas pressure expansion.Where appropriate, the multilayered film and film based assemblyaccording to the present invention can be uniaxially, biaxially ormultiaxially oriented to further enhance its physical characteristics.

For example, in a preferred construction, a multilayered film accordingto the present invention is composed of a coextruded cast film of a corelayer of an EVA copolymer with a VA content of about 28%, an outsidesurface layer of an EO copolymer (e.g., an EO such as the Attane™copolymer manufactured by the Dow Chemical Co., Midland, Mich.) and aninside surface layer of an ethylene-methacrylic acid, zinc or sodiumionomeric copolymer (e.g., an EMAZ or EMAS such as the Surlyn™ copolymermanufactured by DuPont Co., Wilmington, Del.). A three layered film canbe coextruded with the foregoing technique wherein the outside surfacelayer is the EO copolymer and the inside surface layer is the EMAZ orEMAS copolymer. Also, a five-layered film in which the outside surfaceand divider layers are composed of an Attane™ copolymer is preferred

The method for forming a film based assembly includes several steps. Thefirst involves forming a film as a sheet material by coextruding thefirst, second, third and optional divider thermoplastic polymers ascontiguous united layers. In a second step, the molded portion of theassembly is produced by heat bonding two of the sheets in a compressionblow mold having at least two mold halves with at least one havinginternal cavities. Two sheets of the film are placed between the moldhalves with their outside surface layers facing the mold halves andtheir inside surface layers positioned to touch each other when the moldis closed. The molded portion of the assembly is molded by closing themold halves and applying pressure and heat to the sheets while applyinggas pressure to the portions of the sheets within the internal cavities.The self bonding core layers or inside surface layers of the sheet filmsbond to each other and the portions of the sheet films within the moldcavities expand to form the desired internal structure of the moldedportion of the assembly.

The molded portion of the assembly is then bonded to its connective orother preformed parts, which usually is polymeric tubing. In preferredembodiments, the polymeric tubing will also be fabricated fromchlorine-free polymers as described in copending U.S. patent applicationSer. No. 08/103,328, filed on even date with this application andentitled "Multilayered Tubing", the disclosure of which is incorporatedherein by reference. This bonding may be done by appropriate adhesives,or may advantageously be performed by applying a mixture of a polymericbinder and susceptor particles to the apparatus, placing parts of theapparatus, in contact with each other, and subjecting the combination toelectromagnetic radiation. The susceptor particles absorbelectromagnetic energy and generate heat. This heats the polymericbinder material and heat welds the components together. Additionalinformation about the preferred susceptor bonding technique is describedin coassigned U.S. patent applications Ser. No. 07/588,591 (Docket No.43031 USA 6B), 07/668,974 (Docket No. 46736 USA 1A), and Ser. No.07/800,632 (Docket No. 46748 USA 6A), the disclosures of which isincorporated herein by reference.

Preferred Embodiments

FIGS. 1 and 2 show cross-sectional illustrations of two alternativeembodiments of the multilayered films 10 and 20 while FIGS. 3A and 3Bshow top and left side views of a cassette 30 according to the presentinvention. FIG. 1 shows a first embodiment in which multilayered film 10having a core layer 12 of a first, chlorine-free, soft, flexiblethermoplastic polymer contacting an outside surface layer 14 of a secondchlorine-free, tough, durable thermoplastic polymer and an insidesurface layer 16 of a third chlorine-free, self-bonding thermoplasticpolymer. The first thermoplastic polymer is substantially softer thanthe second and third thermoplastic polymers. The surface layers 14 and16 provide tough, protective coatings for the softer, core layer 12. TheYoung's modulus of the first thermoplastic polymer is less than towithin about 250% of that of polyvinyl chloride used in flexibleelastomeric medical applications, preferably in the range of about 15 toabout 50 MPa (megaPascals). The Young's modulus of the second and thirdthermoplastic polymers is higher than but not more than about seven,preferably three times the Young's modulus of the first thermoplasticpolymer, preferably in the range of about 15 to about 150 MPa.

In a particularly preferred embodiment, the core layer of themultilayered film is composed of EVA copolymer and/or(ethylene-butylene) EB copolymer known as Exact™ manufactured by ExxonCorp. Floral Park, N.J. For example, the core layer of the multilayeredfilm 10 (FIG. 1) can be about 200 μ to 325 μ of an EVA copolymer withabout a 20-30% VA content or an EB copolymer, while surface layers 14and 16 respectively can be 50 to 75 μ of an EO copolymer such as anAttane™ copolymer manufactured by Dow Chemical Co. of Midland, Mich. and25 to 100 μ of an EMAZ copolymer such as a Surlyn™ copolymermanufactured by DuPont Co., Wilmington, Del. No adhesive layer isrequired to adhere the core and surface layers 12, 14 and 16 of thismultilayered film 10 together. Instead, upon hot-melt coextrusion, thecore and surface layers readily adhere to one another to form anintegrated three-layered structure. However, if need be, it is alsowithin the scope of the present invention to use an additional material,such as an adhesive, to adhere the core and surface layers and ofmultilayered film and film based assembly together.

FIG. 2 shows a second embodiment of multilayered film and film basedassembly 20 according to the present invention. As with the embodimentillustrated in FIG. 1, this embodiment includes core layer 22 of afirst, chlorine-free, soft flexible thermoplastic polymer contactingoutside surface layer 24 of a second, chlorine-free, tough, durablethermoplastic polymer and inside surface layer 26 of the thirdchlorine-free polymer. In addition, this embodiment contains a dividerlayer 28 in the approximate middle of the core layer 22. The dividerlayer is composed of the second thermoplastic polymer and acts toincrease the stabilization of the core layer during film and film basedassembly formation. This embodiment is especially preferred for use inconstruction of a film based assembly in which precision of the moldedinternal structures is desirable.

FIGS. 3A and 3B show a medical pump cassette embodiment of the filmbased assembly. The medical pump cassette is configured and operatesaccording to disclosure provided by U.S. Pat. No. 4,236,880, thedisclosure of which is incorporated herein by reference. Sheet films 10and 20 formed preferably as depicted in FIG. 2 constitute the work piecefor the molded component. Sheet film 10 is bonded to sheet film 20.Sheet film 10 contains molded tubes 31 and 36 which form the inlet andoutlet of the molded component. Tube 31 connects to bubble 32 which isthe first piston pumping reservoir for the cassette. Bubble 32 isinterconnected to bubble 34 by interconnecting molded tube 33. Bubble 32is the second piston pumping reservoir and connects to outlet moldedtube 36. Medical fluid polymeric tubing 37 and 38 is respectively bondedto molded tubes 31 and 36 to complete the assembly.

The infusion pump cassette 30 has a low level of undesirableextractables. This cassette has a form and function similar to anexisting infusion therapy cassette presently sold by 3M (FIG. 3A). Thiscassette is the metering element of a complete disposable infusiontherapy set which includes tubing, luer locks, spike, drip chamber,clamps, etc. In use, it is inserted into a mechanical metering pump. Itmeets high performance requirements, including those in Table 5 ofExample 5 below.

The cassette of this invention is made from a multilayer polymeric film10, 20 replacing plasticized PVC. This film can be three layers (FIG. 1)or more (FIG. 2) layers, with individual layers composed of single orblended polymers. The composite film construction 10, 20 must have amodulus low enough (for Example, 15 to 50 MPa) to produce fluid chambersthat will pump and roll-back reproducibly, a surface on one side that iscapable of forming a strong heat seal to at least like materials, and asurface on the other that will release from thermoforming molds and/orheat-sealing plates, and serve as an outside protective layer for thefinished cassette. The composite film 10, 20 has sufficient dimensionalstability during the thermoforming and heat seal process of forming thecassette, that a minimum of internal distortion is built into thecassette's internal fluid paths and pumping chambers. The film 10, 20 isalso optically clear to allow nurses to see and remove air bubblesduring priming.

FIG. 4 shows a medical IV bag 40 which is compression mold formed fromtwo sheet films according to the invention. The sheet films are trilayerconstruction in which the inside surface layer 41 forms the insidesurface of the bag while outside surface layer 42 forms the outsidesurface of the bag. Core layer 47 and layers 41 and 42 are coextrudedsuch that they are continuously united. Heat seal 43 along the outsideperimeter of bag 40 is caused by self bonding of core layer 41. Needlespike access 44 is epoxy welded to outlet duct 45 formed in the top 46of bag 40 by jointly forming the heat seal 43, duct 45 and epoxy weldingof access 44.

FIG. 5 shows a complete medical IV tubing assembly 50, including acassette 30 as described above in connection with FIGS. 3A and 3B. Inpreferred embodiments, the other elements which comprise the medical IVtubing assembly 50 will themselves be free of polyvinyl chloride intheir composition. Tubing 52 is provided as a plastic fluid transportingcomponent, preferably its composition is a composite material such asthat discussed in copending and coassigned U.S. patent application Ser.No. 08/103,328, cited above. Such conventional elements as the bag spike54 and the Y-sites 56 may be conveniently made from stiff thermoplasticmaterials; polycarbonate or ABS (acrylonitrile-butadiene-styrene)polymer, are considered particularly suitable. The drip chamber 58requires optical clarity for its function, and e.g., polypropylene,polycarbonate or acrylic polymers may be used. Pinch clamps 60 androller clamps 62 may be provided, and these are conveniently made fromhigh density polyethylene. A slide clamp 64 may be provided,conveniently made from stainless steel.

Susceptor Particle Bonding

A method for susceptible particle bonding of plastic articles is alsocontemplated by the invention. As described above, two thermoplasticarticles can be heat sealed together through the use of susceptorparticles coated at the bonding joint. The susceptor particles absorbelectromagnetic radiation and convert it to heat. The heat in turncauses the heat sealing of the thermoplastic articles. These methodshave been described in U.S. application Ser. No. 07/588,591, U.S. patentapplication Ser. No. 07/668,974, and U.S. application Ser. No.07/800,632, the disclosures of which are incorporated herein byreference. The general methods for forming such a plastic article bondare described in these applications. Generally, the method involvesforming an interlayer of the susceptor particles between the twoportions of the plastic articles which are to be bonded together as ajoint. The joint is then exposed to electromagnetic radiation to causeheat sealing.

For the purposes of the present invention, the susceptor bondingtechnology for assembling the components of the sets provides advantagesover adhesives. The susceptor particles themselves can be made with verylittle metal content, and those metals can be chosen to be biologicallyand environmentally compatible. By proper choice of the polymericbinder, most thermoplastics can be joined together. Typically, thepolymeric binder is comprised of the same materials that the componentsto be joined are comprised. Susceptor technology allows one to heat onlythe bond area of the assembly, the rest of the assembly need not besubjected to heat. Conventional adhesives, such as cyanoacrylates, oneor two part epoxies or UV cure epoxies can contain reactive materialsthat are not medically suitable, can not bond all materials such aspolypropylene or polyethylene, and may require heating of the entireassembly to cause or speed the cure of the adhesive.

Utility of the Invention

Multilayered film and film based assembly according to the presentinvention can be utilized in a wide range of both medical and nonmedicalproducts. In the medical area the multilayer film and film basedassembly is suitable for replacing chlorine-containing PVC film and filmbased assembly, such as is utilized with intravenous (IV) fluidadministration sets, infusion sets, cassettes, blood bags, IV fluidbags, arthroscopy fluid control systems, cardiovascular systems andblood gas monitoring systems. UV absorbers can be added to one or moreof the layers of multilayered film and film based assembly forapplication in IV sets used with light-sensitive drugs. This adaptationof the multilayer film and film based assembly will not absorb drug ormedical fluids and will not contaminate the drug or medical fluid withadditive, plasticizer and the like through extraction or leaching.

These and various other advantages and features of the invention arepointed out broadly by the foregoing general specification. Thefollowing examples are provided to further illustrate the invention.These examples are not meant to limit the broad scope of the invention,however.

EXAMPLE 1 An EVA Core Trilayer Film

A 375 μ trilayer film was co-extruded from three polymers: a top layerconsisting of a 50 μ layer of an ultra low density co-polymer ofethylene and octene (Dow Attane™ 4602), a 275 μ core layer of a soft EVA(28% VA) (Quantum UE-645-04), and an inside, heat seal layer consistingof a 50 μ layer of an ionomer resin that is a co-polymer of ethylene andmethacrylic acid doped with zinc (Dupont Surlyn™ 1702). A 20 cm widethree manifold adjustable vane die was used. The Attane™ 4602 was fed toone of the outside manifolds of the die by a 2.5 cm Killion™ singlescrew extruder using a conventional screw (Killion, Inc., Verona, N.J.);the Surlyn™ was fed to the other outside manifold by a similar extruder;the EVA core was supplied to the middle chamber from a 30 mm co-rotatingtwin screw extruder compounder (37:1 L/D) with a Zenith pump formetering.

The temperature profiles for these three extruders is given in Table 1.(Unless otherwise indicated the extruder conditions for film formationaccording to each Example are given in Table 1.) The co-extruded filmwas cast onto a 30 cm diameter chrome roll held at a temperature of 12°C., and then immediately passed through a nip between this chrome rolland a rubber roll.

To estimate the best cassette forming conditions for this film, a simplelaboratory-scale forming device was used. This device (shown in FIG. 6)consists of two aluminum blocks that can be held together by wing nuts.The lower block has a small cylindrical hole, or well, into which thefilm can be thermoformed when heat and air pressure is applied. The topblock was fitted with an air pressure connection. The film layers wereplaced in the former (centered over the cylindrical hole), with theSurlyn™ copolymer sides facing one another, and the Attane™ copolymersides facing the aluminum blocks. A hole had been cut in the upper filmlayer to allow pressurized air to get between layers. An O-ring wasplaced over the film sandwich, centered over the hole in the film andthe hole in the lower block. A thermocouple was placed between the filmlayers, and positioned adjacent to the O-ring. The top block was thenplaced down over the O-ring and film assembly and tightened down by wingnuts. This formed a pressure seal around the sample above the deflectionwell. The air inlet port of the device was connected to compressed air.The air pressure was adjusted to 3 psi (0.2 kg/cm²) using an in-linegauge. This assembly was then put into a Despatch oven set at 121° C.and heated until the thermocouple read 93° C. (18 minutes). The wholeassembly was then immediately immersed in room temperature water toquench the construction.

This experiment was repeated several times, each time with a higherfinal ("formation") temperature. The details are summarized in Table 2.

Complete chamber formation at 106° C. and 116° C. means the filmcompletely filled the well and took its shape. Partial formationtypically means the film formed domes which were smaller than the well.The heat seal between the layers occurred under the O-ring, takingessentially the shape of the O-ring. At 106° C. and 116° C., the sealbetween the layers was strong. When an attempt was made to pull the twohalves of these films apart at the heat seal, the film itself tore andappeared to separate internally, rather than within the seal itself. Thefilm released readily from the aluminum mold halves. In subsequentexperiments, a heat gun was used to heat the assembly. Using the heatgun, samples could be heated to 107° C. within 5 minutes.

Cassettes were then made from this trilayer film using a productionformer. Since the former is 107/8" (27.6 cm) wide, two of the 8" (20.3cm) films were spliced together using a thermally stable polyestersplicing tape. The cassettes were prepared as configured in FIGS. 3A and3B, and were fabricated by blow molding between two forming plates. Theforming plates of the production former were two aluminum mold halveswhich were provided with a 2 by 5 array of cavities each appropriate tothe shape of the final desired shape of the top and bottom halves of thecassette respectively.

These plates were mounted in a hydraulic press, and provision made toheat the plates by cartridge heaters within the respective platenssupporting the plates. At the completion of the heating phase, coolingwater was circulated through the backing of the plates to quench thethermoformed construction rapidly. The two films were placed over thebottom mold half with their Surlyn surfaces in contact with each other,and their Attane surfaces facing the mold plates, which were initiallyat room temperature. Two small (1/16" dia) (1.6 mm) air tubes wereinserted between the edges of the film in a slot cut into the mold, soas to inject air along a pair of air delivery runners cut into the moldhalves. The top half of the mold was brought down on the film pair andhydraulic pressure of 6 tons (5500 kg) applied. Air pressure between thefilms was maintained at a pressure above about 0.42 kg/cm² (6 psi) toforce the films into the mold cavities as the temperature of the plateswas ramped up. The temperatures of the top and bottom mold halves wereramped up together. When the pre-set final temperature (or "formation"temperature) was reached, the cartridge heaters were turned off, andcooling water was flushed through the plates to bring them back to alower temperature, while still maintaining hydraulic ram pressure andinternal air pressure. Once a temperature was reached at which theconstruction was dimensionally stable, the molds were separated and thecassettes were removed.

Two pairs of these films were run on this former. On the first pair, thefinal plate temperatures were: 120.5° C. top plate/120° C. bottom plate;the plates were cooled to 57° C. before removing. With the second pair,the plates were heated to 107° C. top plate/108° C. bottom plate, andremoved at 57° C. In both cases, an air pressure of 6 psi and ahydraulic ram pressure of 6 tons was used, with an overall cycle time of5 minutes. Flexible cassettes, with well formed, flexible chambers, openfluid paths and strong heat seals were formed from both experiments.

EXAMPLE 2 An EO Outside Surface Layer Trilayer Film

A 375 μ trilayer film consisting of a 50 μ top layer of Attane™ 4602, a275 μ core layer of EVA(28% VA), and a 50 μ layer of a lower modulusionomer (Dupont Surlyn™ AD-8255) was co-extruded using the equipmentdescribed in Example 1. The extruder conditions which prevailed arenoted in Table 1.

Experiments using the laboratory-scale forming device were performedwhich paralleled those discussed in Example 1. The results aresummarized in Table 3.

Chambers formed were complete, and were more flexible than those fromthe construction of Example 1. Heat seals were strong: seals did notseparate, even after they were pulled to the point that the films tore.

Cassettes were then made from these films, using the production formerdescribed in Example 1. Formation temperatures were: 115.5° C. topplate/116.5° C. bottom plate;. an internal air pressure of 0.42 kg/cm²(6 psi), and a ram pressure of 6 tons (5500 kg) was used; cycle time was5 minutes. Cassettes with well formed chambers, open fluid paths andstrong heat seals were formed. The chambers of these cassettes weresomewhat more flexible than those of Example 1.

EXAMPLE 3 Third Trilayer Film

A 375 μ trilayer film consisting of a 50 μ layer of Attane 4602, a 275 μlayer of EVA (28% VA) and a 50 μ layer of Surlyn AD-8255 wasco-extruded, using a 30 cm wide die. The center EVA layer was suppliedto a Cloeren feed block from a 3.2 cm Brabender Extruder (C. W.Brabender Instruments, South Hackensack, N.J.) with a positivedisplacement pump. The Surlyn and Attane were supplied from 2.5 cm Wayneextruders (Wayne Machine and Die Co. of Totoya, N.J.) with 1.168 ccZenith PEP pumps. The layered feed was then fed through a 30 cm singlemanifold extrusion die (Extrusion Dies, Inc. of Chippewa Falls, Wis.)The co-extruded melt was cast onto a 10 cm diameter chrome roll kept atroom temperature, and then run through a nip between a rubber roll andthe chrome roll. The run speed was 2 meters/min. Extruder conditions areshown on Table 1.

Cassettes were prepared on the production former, as described inExample 1, except that final formation temperatures on the plates were99° C. on the top plate and the bottom plate. An array of flexible,apparently well formed cassettes was obtained, that appeared to havegood fluid seals and channels between chambers.

Samples of these cassettes were connected with IV tubing, and thentested for performance in a 3M AVI 200A IV Infusion Pump. The tubingconnected to the inlet of the cassette was connected through asyringe/luer lock to an IV solution bag, placed 46 cm above the pump.The exit tube from the cassette was run to the top of a 50 ml burette,with the top of the burette level with the bottom of the pump. Thecassette was primed by first sealing the exit tube with a clamp and thensqueezing the air out of the cassette and filling with fluid from thebag. The cassette was inserted in the infusion pump and the door wasclosed. The pump was set to a volume limit of 49 ml and a pumping rateof 500 ml/hour, and then activated. The water delivered by the pump andcassette combination was collected in the burette and measured. Thepump/cassette combination delivered 49 ml and then stopped.

The same cassette was then endurance tested. A closed loop was made byconnecting both ends of the tubing to an IV bag. The pump was set topump at the maximum rate (999 ml/hr) and maximum pressure and pumpedcontinuously for 72 hours. During that period, the cassette appeared tobe functioning perfectly and showed no sign of fluid leakage or internalrupture of seals.

EXAMPLE 4 Low Modulus EMAZ Trilayer Film

A 375 μ trilayer film consisting of a 50 μ layer of Attane 4602, a 275 μlayer of EVA (28% VA) and a 50 μ layer of a very low modulus ionomer,Dupont Surlyn 8320 was co-extruded, using the 30 cm extruder/diedescribed in Example 3. Extruder conditions are given in Table 1.

Cassettes were made from these films on the production former, varyingthe formation conditions to begin seeking an optimum set of conditions.Formation temperatures of 104° C.±6° C. were tried; it was found to beadvantageous to remove the samples from the press at temperatures asclose to room temperature as possible, to minimize distortion of thechambers; in all cases, the plates were chilled immediately afterreaching the final (formation temperature). Samples were produced thatappeared to be well formed and sealed, and had a flexibility approachingthat of cassettes made with the plasticized PVC film.

Samples of these cassettes were connected with IV tubing, and thentested for performance in a 3M AVI 200A IV Infusion Pump in the mannerdescribed in Example 3. Some of the samples appeared to pump adequately,but continued to drip after the pump was shut off. These samples werecross-sectioned in the fluid paths between the chambers, and examinedunder an optical comparator (Nikon Profile Projector Model V-12, with aNikon SC-102 digital readout scanner). It was found that there was aslight distortion of the films in the corner of the fluid path (FIG. 3a,reference numeral 33) in those cassettes which had not shut offcompletely. Mechanical valves close on these fluid paths and aresupposed to press the two films completely together. However, thisslight distortion around the heat seals is enough to prevent the fluidpath from being completely closed off with the closing force of thecurrent pump. This defect occurred in some but not all of the cassetteswithin a molding array, and is correctable by tuning the formingprocess, i.e., by making adjustments to get uniform sealingtemperatures, seal force, and proper heating rate, and the like.

EXAMPLE 5 A Five Layer Film and Cassette

In an endeavor to structurally account for the slight internaldistortion of the films during the forming process, a five-layermodification of Example 4 was made. It is believed that at least some ofthe distortion described in Example 4 is a result of distortion, orpossibly flow-out of the soft EVA in areas adjacent to the heat seals.To try to reduce this, a single 25 μ layer of the higher softeningtemperature Attane 4602 copolymer was added to the center of the EVAcore. Thus a construction of: 50 μ Attane 4602/100 μ EVA(28% VA)/25 μAttane 4602/125 μ EVA(28% VA)/75 μ Surlyn 8320 was made. First atrilayer of 50 μ Attane/100 μ EVA/25 μ Attane was co-extruded on a 91 cmextruder. A two manifold die was modified to accomplish this. Attane wasdelivered to the top manifold of the die directly from a 3.2 cm extruder(Killion KLV-125 L/D 30:1, from Killion, Inc. of Verona, N.J.) using aconventional screw. The EVA was extruded from a 6.4 cm extruder (L/D30:1 from HPM Corporation of Mt. Gilead, Ohio) through a feed tube andfeed block to the lower manifold of the two chamber co-extrusion die.The lower (25 μ) Attane layer was added by feeding from a 2.5 cmextruder through a 1.25 cm tap in the bottom of the feed tube to thelower manifold. A pigment was added to the lower Attane layer to helpdetermine distribution of the layer, and to distinguish it from theother layers in a microscopic examination of the film cross-section. Thelower two-component melt then was joined with the upper Attane layer atthe exit to the die. The melt was cast onto a 40 cm chrome rollmaintained at room temperature and then passed through a nip between ateflon roll and the chrome roll. Run speed was 2 m/minute. The fivelayer construction was then completed by co-extruding a 125 μ EVA/75 μSurlyn layer onto the first trip film, with the Surlyn being suppliedfrom the 3.2 cm extruder and the EVA from the 6.4 cm extruder. Variouscasting roll temperatures were tried, but it was found that roomtemperature on the roll produced an excellent film. Second trip runspeed was also 2 m/minute. Extruder conditions are given in Table 1.This film was slit to 27.6 cm.

Cassettes were made from this film, using the production former. Twosets of cycle conditions were used, which conditions are summarized inTable 4.

Sample cassettes were taken from various plate locations within eachimpression, and from the same location in several impressions. Thesewere connected into a complete IV set and volumetrically tested. Amodification of the volumetric test of Example 3 was used. As in Example3, the IV bag was 46 cm above the top of the pump; the water was pumpedinto the top of a 50 ml burette; the top of the burette was 76 cm" belowthe IV bag. The pump was set to deliver 40 ml and fluid was pumped at arate of 500 ml/hour. The fluid delivered was then measured in theburette. Following this delivery, the pump automatically goes into avery low rate pumping cycle of 1.0 ml/hour, which is called "keep thevein open (KVO)". Its purpose is to continue delivering a small volumeof fluid to the vein to prevent occlusion within the needle. Theadditional fluid delivered during 20 minutes of this cycle was thencollected and recorded, and from this, a KVO delivery rate wascalculated. Table 5 is a summary of the volumetric accuracy of theserandomly selected samples. The first column lists the actual volumesdelivered, when the pump had been set to deliver 40 ml. The secondcolumn lists the measured rate of delivery during the KVO cycle. (Thedesired KVO rate is 1.0 ml/hour.)

EXAMPLE 6 A Five-Layer Low Melt Film and Cassette

A five-layer film sample was made in which a different ethylene/octenecopolymer, the lower melt index Dow Attane 4601, was substituted for theAttane 4602 of Example 5. The purpose of this substitution was tominimize the tendency of the film to fill tiny vent holes in the formingplate, that occurs after repeated forming with film having a 4602release layer. This film was extruded on the 20 cm extruder of Example1, using a two trip process similar to that of Example 5.

Extruder conditions are listed in Table 1. This film was tested on thelaboratory former, described in Example 1. 0.42 kg/cm² (6 psi) internalpressure was used. When the sample was heated to a final temperature of97° C., there was nearly complete chamber formation, and a strong heatseal was formed. There was complete chamber formation at 102° C. Thefilm released easily from the aluminum forming plate.

EXAMPLE 7 A Five-Layer EB Film and Cassette

A five-layer film sample was made in which an ethylene-butene copolymer(Exxon Exact 4028) was substituted for the EVA of Example 5. This filmwas extruded in the manner of Example 6 (Extruder conditions listed inTable 1), and tested on the laboratory former described in Example 1.Internal pressure of 0.42 kg/cm² (6 psi) was used. At a formationtemperature of 94° C., there was nearly complete formation, with goodheat seals. At a formation temperature of 102° C., there was completeformation with good heat seals.

EXAMPLE 8 Comparative Single Layer Film

A 375 μ film of pure EVA (28% VA) (Quantum UE-645-04) was extruded fromthe 30 cm extruder setup of Example 3 (using only the BrabenderExtruder). Cassettes were made on the production former, using formationtemperatures ranging from 64-70° C., and a total cycle time of 2.5 to3.5 minutes (Table 1). Cassettes were formed that exhibited medium tolow seal strength (1.8 kg tensile at 70° C. forming temperature; 0.70 kgtensile at 64° C. forming temperature). They had a high adhesion to themold, and had a somewhat tacky surface feel.

EXAMPLE 9 Comparative Single Layer Film

A 375 μ film was made of an ethylene/butene copolymer (Exxon Exact 4024)from a single chamber of the 8" extruder of Example 1. (Conditions:Table 1.) These films were tested on the laboratory former to determinethe best formation temperature. Results of these tests are summarized inTable 6.

Films were spliced together in the manner of Example 1 and an attemptwas made to form cassettes on the production former, with threedifferent formation temperatures. The results are summarized in Table 7.Under these conditions, chamber formation varied across a single platefrom partial formation (dome) to complete formation with bases brokenoff adjacent to the heat seals. Heat seals between the films were verystrong at the highest formation temperatures; the films showed moderateadhesion to the forming plate.

EXAMPLE 10 Comparative Single Layer Film

A 375 μ film was made of an ethylene-methyl acrylate copolymer (EMAC2205, commercially available from Chevron Chemical Co. of Houston,Tex.), using the center manifold of the 20 cm extruder of Example 1.Extruder conditions are listed in Table 1. Laboratory tests were run onthis film, using the methods described in Example 1. In all tests, 0.42kg/cm² (6 psi) internal pressure was used. Complete formation occurredat 77° C., with a thin but intact chamber formed. However, there wasconsiderable flow out in the area under the o-ring (the "heat sealarea"). In this area, only a thin film was left. At 85° C. a similarformation occurred, with a very thin layer left in the heat seal area,and a slightly thinner bottom on the chamber. At 96° C., the heat sealarea had broken through entirely, and the chamber separated completelyfrom the rest of the film. Adhesion to the mold was low in all threecases. Two of these films were spliced together as described previously,and tested on the production former. With final formation temperaturesof: bottom plate: 86° C., top plate: 90° C., partial formation occurred.There was separation of the "chambers" (actually domes) at their baseson some of the impressions. There appeared to be strong heat sealing ofthe two films in all areas of the plate. The samples came out of themold with low adhesion.

EXAMPLE 11 Comparative Single Layer Film

A 375 μ film was made of another ethylene-methyl acrylate copolymer(EMAC 2260, commercially available from Chevron Chemical Co. of Houston,Tex.) using the center manifold of the 20 cm extruder of Example 1.Extruder conditions are listed in Table 1. Laboratory tests showed thatthere was partial formation at 88° C. and 0.42 kg/cm² (6 lbs) pressurewith a good heat seal. The dome that formed was stiff, compared to theEMAC 2205. Adhesion to the mold was low.

EXAMPLE 12 A Tri-Layer Film

A tri-layer film was formed under circumstances wherein the core layeralso acted as an inside surface layer. In this case, the firstthermoplastic polymer used also had appropriate self-bonding and tensilestrength characteristics. The film included a 50 μ layer of Attane 4602and an 275 μ layer of an ethylene-butene copolymer (and EB copolymer ofthe tradename Exact 4024). The film was made on the 30 cm extruder bythe process described in Example 3, with the third extruder thatsupplied the Surlyn turned off. The film was soft and flexible, andformed cassettes using a formation temperature of 102° C. Unlike thesingle layer Exact 4024 film of Example 9, this tri/bi-layer film didnot adhere to the aluminum mold. The Attane 4602 at these formationtemperatures, acted as a "mold-release", and did not appear to adverselyaffect the ability of the softer and tackier EB to take the shape of themold. Extruder conditions are listed in Table 1. Samples of this filmwere tested on the laboratory former. A formation temperature of 102° C.was used with 0.42 kg/cm² (6 psi) of internal pressure. Completeformation occurred, with strong heat seals, not only under the o-ring,where pressure was applied, but wherever the films came in contact. Thechamber formed looked quite uniform, and was quite optically clear.

EXAMPLE 13 An EMAC Tri/bi-Layer Film and Cassette

A trilayer film was formed under circumstances where the core layer alsoacted as an outside surface layer. In this case, the first thermoplasticpolymer used also had appropriate mold release and abrasion resistancecharacteristics. The film included 275 μ of ethylene-methyl acrylatecopolymer (EMAC 2205) and 100 μ Surlyn (EMAZ 8320). The film was made onthe 30 cm extruder of Example 3. Extruder conditions are listed inTable 1. Samples of this film were tested on the laboratory former.Samples were formed at 77° C. and 0.42 kg/cm² (6 psi) of internalpressure. Chamber and seal formation were complete. The addition ofSurlyn 8320 appears to have strengthened the film in both the chamberand heat seal areas, compared to cassettes made from EMAC alone, seeExample 10.

The Surlyn adds both a degree of toughness and dimensional stability tothe film without greatly increasing its stiffness. The EMAC 2205 softensat 59° C. and melts at 83° C. The Surlyn 8320 seals at 72° C. Thus thiscombination makes it possible to use a lower formation temperature (77°C.) than in the previous Examples (92° C.). Further, in this Example,the overall film softening and sealing temperatures are closer togetherthan in the previous Examples. Note that the EMAC in this material isacting as both core and outer surface/release layer.

EXAMPLE 14 An EMAC/Blended EVA Trilayer Film

A trilayer film of 50 μ EMAC 2205, 225 μ of a blend of 75% EVA (28%VA)/25% EVA (19% VA), and 100 μ of Surlyn 8320 was made on the 30 cmextruder of Example 3. The two EVA resins were blended by hand, and thenadded to the hopper of the center layer Brabender extruder. The extruderconditions are listed in Table 1. Samples of this film were tested onthe laboratory-scale former with a temperature of 74° C. and a pressureof 0.42 kg/cm² (6 psi). Complete formation occurred, with strong heatseals. The film assembly released readily from the aluminum plates.

EXAMPLE 15 An EO Trilayer Film

An ABC trilayer film was made from Attane 4602 (A) (50 μ),ethylene-methyl acrylate copolymer (EMAC 2205)(B) (225 μ), and SurlynAD-8255 (C) (50 μ), using the 20 cm extruder described in Example 1.Extruder conditions are listed in Table 1. Laboratory-scale tests wererun on this film, using the methods of Example 1. At a formationtemperature of 96° C., there was nearly complete formation withexcellent heat seals. At 102° C., there was complete formation withexcellent heat seals. Two of these films were spliced together asdescribed previously, and tested on the production former. 0.42 kg/cm²(6 psi) of internal pressure was used. Formation temperatures were:bottom plate 113° C./top plate 108° C. Partial formation occurred, butthere was no sign of the weakened chamber bases found in Example 10 withthe EMAC alone. Strong heat sealing occurred only in the areas whereheat sealing is expected, i.e., the fluid seals on the perimeter of thechambers and connecting fluid paths.

EXAMPLE 16 Adhesive Bonding of Tubing and Cassette

Tubing made according to Example 8 of U.S. patent application Ser. No.08/103,328 cited above, was bonded to a cassette prepared according toExample 5 above. The two components of a two-part epoxy adhesivecommercially available as TRA-BOND FDA-2 from Tra-Con, Inc. of Medford,Mass., were mixed and a small amount was applied to one end of the tube.This treated end was inserted into one of the molded tubes in thecassette, and the assembly allowed to cure for 15 minutes at 65° C., andthen for 12 hours at 25° C.

EXAMPLE 17 Testing of Assembly

The assembly of Example 16 was tested for bond strength and integrity byfilling the lumen of the tube and the cassette with air, and subjectingthe air to a pressure of 10 psi (0.70 kg/cm²). The bond was submerged inwater and examined visually for leaks revealed by emitted bubbles. Afterthe visual inspection, the pressure was released, and an 8 pound (3.6kg) weight was hung from the assembly so as to stress the bond. Theassembly was visually inspected for signs of bond separation. Then thelumen of the tube and the cassette was repressurized with air to apressure of 10 psi. Again, the bond was submerged and examined visuallyfor leaks. Bonded constructions according to Example 16 were able tosuccessfully pass the three aspects of this test, and were thus deemedto be suitable for use in medical tubing assemblies.

EXAMPLE 18 TriLayer EMAC/SURLYN Blend Film and Cassette

A tri-layer film sample of 50 μ of EMAC 2205, 225 μ of a blend of 70%EMAC 2205/30% Surlyn 8320, and 100 μ of Surlyn 8320 was made on the 30cm extruder setup according to Example 3. The EMAC and Surlyn resinswere blended by hand and then added to the hopper of the center layerBrabender Extruder. Extrusion conditions are described in Table 1. Thefilm was tested on the laboratory-scale former according to Example 1,with an internal pressure of 0.42 kg/cm² (6 psi) and a temperature of77° C. being used. Complete formation occurred with strong heat seals,and a ready release from the plate.

EXAMPLE 19 Tri/Bilayer Film and Cassette

A tri/bilayer film sample of 50 μ of EMAC 2205 and 325 μ of Surlyn 8320was made on the 30 cm extruder setup according to Example 3. Extrusionconditions are described in Table 1. The film was tested on thelaboratory-scale former according to Example 1, with an internalpressure of 0.42 kg/cm² (6 psi) and a temperature of 79° C. being used.Complete formation occurred with strong heat seals. The cassette wasquite flexible, and appeared to spring back readily after beingcompressed by hand.

EXAMPLE 20 TriLayer EVA Film and Cassette

A trilayer film sample of 50 μ of EMAC 2205, 225 μ of EVA (28% VA), and100 μ of Surlyn 8320 was made on the 30 cm extruder setup according toExample 3. Extrusion conditions are described in Table 1. The film wastested on the laboratory-scale former according to Example 1, with aninternal pressure of 0.42 kg/cm² (6 psi) and a temperature of 77° C.being used. Complete formation occurred with strong heat seals, and thefilms released readily from the plate.

EXAMPLE 21 Adhesive Bonding of Tubing and Cassette

Tubing and a cassette according to Example 16 above were bonded to eachother, but this time with a cyanoacrylate adhesive commerciallyavailable as Permabond from National starch and Chemical Corporation ofEnglewood, N.J. A small amount of the adhesive was applied to one end ofthe tube, and the treated end was inserted into one of the molded tubesin the cassette. The construction was then allowed to complete the curefor 12 hours at 25° C. The bond was then tested in the fashion describedin Example 17, and found to have bond strength and integrity andadequate for its purpose in medical tubing assemblies.

EXAMPLE 22 Epoxy Bonding of Tubing and Cassette

Tubing and a cassette according to Example 16 above were bonded to eachother, but this time with a UV curing epoxy adhesive commerciallyavailable as UV6010 from Polychem Corp. of Cranston, R.I. A small amountof the adhesive was applied to one end of the tube, and the treated endwas inserted into one of the molded tubes in the cassette. The treatedarea was then subjected to high intensity UV light shown through thewall of the cassette for one second. The assembly was then allowed tocomplete the cure for 12 hours at 25° C. The bond was then tested in thefashion described in Example 17, and found to have bond strength andintegrity and adequate for its purpose in medical tubing assemblies.

EXAMPLE 23 Second Epoxy Bonding

Tubing and a cassette were bonded according to Example 19, with theexception that the UV curing epoxy adhesive was instead one commerciallyavailable as L-4240 from ICI of Wilmington, Del. Adequate bond strengthand integrity was achieved.

EXAMPLE 24 Susceptor Particle Bonding of Tubing and Drip Chamber

One sixteenth inch (1.6 mm) glass fibers commercially available as 739DD from Corning Co. of Corning, N.Y. were coated with a thin layer ofstainless steel as described in U.S. patent application Ser. No.07/668,974 (FN 46736USA1A) to form susceptor particles. These fiberswere mixed into an ionomer commercially available as Surlyn AD 8255 fromE.I. Dupont and Nemours of Wilmington, Del. at a volume loading of 20%.A Haake Rheocord System Model 600, commercially available from Haake ofSaddlebrook, N.J., was used to make this composite. A small amount ofblue pigment concentrate in low density polyethylene was also used togive the composite a blue color. This composite is the susceptorparticle filled bonding material.

A strip of this susceptor particle filled bonding material which wasabout 0.010" (0.25 mm) thick and 3 millimeters wide was placed aroundthe tip of a polypropylene drip chamber commercially available fromMedlon of Burbank, Calif. Tubing made according to Example 46 of U.S.patent application Ser. No. 08/103,328 cited above, e.g., a three layertubing with Surlyn AD 8255 on the inside and outside surfaces andQuantum UE645 EVA in the core, was slipped over this.

This assembly was placed in a small coil of a Lepel T-2.5-1-MC-B3W(T)induction heater, commercially available from Lepel, of Edgewood, N.Y.,set to the 5 to 8 MHz frequency range. The induction heater had a gridcontrol setting of 66, plate current of 0.50 amps, and grid current of142 milliamps. The coil was oval in shape with 4 turns of 1/8 inch (3.2mm) outside diameter tubing with inside opening of 11/2" (3.8 cm) wideby 7/8" (2.2 cm) high by 5/8" (1.6 cm) deep. Power to the inductionheater coil was turned on for 2.25 seconds. This melted the susceptorparticle, filled bonding material and the surfaces of the tubing anddrip chamber, forming a good bond. This bond then passed subsequenttesting as described in Example 17 for bond strength and leak integrity.

EXAMPLE 25 Susceptor Particle Bonding of Tubing and Luer Lock

Glass fibers coated with a thin layer of stainless steel as described inExample 24 were incorporated into a hot melt adhesive commerciallyavailable as Euremelt 2140 from Schering-Berlin of Lakeland, Fla., at avolume loading of 20%. A strip of this susceptor particle filled bondingmaterial which was about 0.010" (0.25 mm) thick and 3 millimeters widewas placed around the end of a piece of the trilayer tubing described inExample 24. This tubing with bonding material was slipped into a luerlock made of ABS. This was placed in the induction heater coil describedabove and power was applied to the coil for 2.5 seconds. This heated thesusceptor particle filled bonding material and bonded the tubing to theluer lock. This bond then passed subsequent testing according to Example17 for bond strength and leak integrity.

EXAMPLE 26 Susceptor Particle Bonding of Tubing and Drip Chamber

Glass fibers coated with a thin layer of stainless steel as described inExample 24 were incorporated into a hot melt adhesive commerciallyavailable as JetMelt 3748 from the 3M Company of St. Paul, Minn., at avolume loading of 20%.

A strip of this susceptor particle filled bonding material which wasabout 0.010" (0.25 mm) thick and 3 millimeters wide was placed aroundthe tip of a polypropylene drip chamber commercially available fromMedlon of Burbank, Calif. Tubing made according to Example 8 of U.S.patent application Ser. No. 08/103,328 cited above, e.g., a trilayertubing with Surlyn 8320 on the inside and outside surfaces and Exact4028 EB in the core, was slipped over this.

A model 2274A microwave generator commercially available from Litton ofMemphis, Tenn. was set to deliver 700 watts at a frequency of 2.45gigahertz for 60 seconds. The bond thus created then passed subsequenttesting according to Example 17 for bond strength and leak integrity.

EXAMPLE 27 Susceptor Particle Bonding of Tubing and Cassette

A susceptor particle bonded assembly was prepared as in Example 24,except that the tubing was bonded to a cassette made according toExample 16. This bond then passed subsequent testing according toExample 17 for bond strength and leak integrity.

EXAMPLE 28 Susceptor Particle Bonding of Tubing and Chamber

Ferromagnetic amorphous powders were been produced as described in U.S.patent application Ser. No. 07/800,632 (FN 46748USA6A) to form susceptorparticles. The susceptor particles had an alloy composition of Fe₆₈.5Cr₈.5 P₁₅ C₅ B₃ (in atomic percentage). These powders have a Curietemperature of ≈130° C. and particle sizes below 44 micron (or below 325mesh). These powders were mixed into Quantum UE645 EVA at a volumeloading of 8%. A small amount of green pigment concentrate in lowdensity polyethylene was also used to give the final composite a greencolor. This mixture was compounded in a two rolls rubber millmanufactured by S. Bolling, Cleveland, Ohio, and extruded into tubingshaving approximately a 10 mil (0.25 mm) wall thickness, and 0.150" (3.8mm) outside diameter. These tubings become the amorphous powders filledbonding materials.

A piece of this bonding material which was about 3 millimeters long wasplaced into the tip of a polypropylene drip chamber as described inExample 23. Tubing made according to Example 46 of U.S. application Ser.No. 08/103,328 cited above, e.g. a trilayer tubing with Surlyn AD 8255on the inner and outer surfaces and Quantum UE645 EVA in the core, wasslipped over this.

A dozen samples of this assembly were placed in a rectangular coil of anEmabond P-005-09 induction heater set. This Emabond system has a fivekilowatt power supply in the 3 to 7 MHz frequency range. The coil isrectangular shape with 3 turns of 6"×2". Power to the induction heatercoil was energized for about 30 seconds. This melted the bondingmaterials and the surfaces to the tubing and drip chamber, forming agood bonding. This bond passed subsequent testing as described inExample 17 for bond strength and leak integrity.

EXAMPLE 29 Susceptor Particle Bonding of Tubing and Cassette

Ferromagnetic powders as described in Example 28 were mixed into anionomer commercially available as Surlyn 1702 from E.I. Dupont andNemours of Wilmington, Del. at a volume loading of 8%. A C. W. Brabendermodel 5000 mixer was used to make this composite. Portion of thiscomposite was then hot pressed by using a Carver Laboratory Press model2699 commercially available from F. S. Carver of Wabash, Ind. into athin sheet of about 0.010" (0.25 mm) thickness. This sheet of compositeis the susceptor powder filled bonding materials.

A strip of this ferromagnetic amorphous powder filled bonding materialwhich was about 0.010" (0.25 mm) thick and 3 millimeter wide was placedaround the tubing which was made according to Example 10 of U.S.application Ser. No. 08/103,328 cited above, e.g. a three layer tubingwith Surlyn 9320 on the inner and outer surfaces and Exact 4028 thecore. This tubing with the bonding material was slipped into an cassettewhich was made according to Example 5 above. Several of these assemblieswere placed in the induction heater as described in Example 28 for 30seconds. This melted the bonding materials and the surfaces to thetubing and cassette, forming a good bonding. This bond passed subsequenttesting as described in Example 17 for bond strength and leak integrity.

EXAMPLE 30 Susceptor Particle Bonding Tubing and Cassette

A bond assembly was prepared according to the procedure of Example 28,except that the tubing was bonded to a cassette prepared according toExample 5 above. This bond passed subsequent testing as described inExample 17 for bond strength and leak integrity.

EXAMPLE 31 Susceptor Particle Bonding of Tubing and Chamber

A bonded assembly was prepared a Example 29, except that the tubing wasbonded to a drip chamber as described in Example 28. This bond passedsubsequent testing as described in Example 17 for bond strength and leakintegrity.

EXAMPLE 32 Susceptor Particle Bonding of Tubing and Luer Lock

A bonded assembly was prepared according to the procedure of Example 28,except the tubing was bonded to a luer lock. This bond passed subsequenttesting as described in Example 17 for bond strength and leak integrity.

EXAMPLE 33 Susceptor Particle Bonding of Tubing and Luer Lock

A bond assembly was prepared as in Example 29, except that the tubingwas bonded to a luer lock fabricated from ABS polymer. This bond passedsubsequent testing as described in Example 17 for bond strength and leakintegrity.

EXAMPLE 34 Particle Bonding of Single Layer Tubing to Drip Chamber

Suzorite mica flakes, from Suzorite Mica Products, Inc. in Hunt Valley,Md., were coated with a thin layer of stainless steel as described inU.S. patent application Ser. No. 07/668,974 cited above. These coatedmica flakes were then mixed into Quantum UE645 EVA (28% vinyl acetate)at a volume loading of 10%. Red pigment and titanium dioxide were addedto the composite to impart a red color. A thin layer of this coatedparticle susceptor bonding material was placed in the bond area of adrip chamber made from Rexene 1903 EVA (9% vinyl acetate). Tubing madefrom Quantum UE645 EVA was placed over this. This assembled componentwas placed in the coil of the LEPEL induction heater for 2.25 seconds.The coil was made with 1/8" (3 mm) OD copper tubing. It had 5 turns, theinner diameter of the coil was 0.5" (13 mm), the length of the coil was7/8" (22 mm). The settings on the LEPEL were Grid Control 76, platecurrent 0.48 amps, grid current 120 milliamps. The susceptor filledbonding material heated and bonded the two components together, so thatit passed the test described in Example 17.

EXAMPLE 35 Five-Layer Film and Cassette

A five-layer film sample was made according to Example 5, except thatzinc-doped, low modulus Surlyn 9320 was substituted for the Surlyn 8320.Extrusion conditions are described in Table 1. The film was tested onthe laboratory-scale former according to Example 1, with an internalpressure of 0.42 kg/cm² (6 psi) being used. At a formation temperatureof 94° C., there was partial formation; at a formation temperature of101° C., there was complete formation with good heat seals.

EXAMPLE 36 EMAC TriLayer Film and Cassette

A trilayer film sample of 50 μ of Attane 4601, 275 μ of EMAC 2260 and 50μ of Surlyn AD 8255 was made on the 30 cm extruder setup according toExample 3. Extrusion conditions are described in Table 1. The film wastested on the laboratory-scale former according to Example 1, with aninternal pressure of 0.42 kg/cm² (6 psi) and a temperature of 99° C.being used. Complete formation occurred with strong heat seals,excellent release from the plate, and excellent clarity.

EXAMPLE 37 Susceptor Particle Enhanced Curing of Epoxy

Glass fibers coated with a thin layer of stainless steel were madeaccording to Example 21 above forming susceptor particles which weremixed into TRA-BOND FDA-2 epoxy, discussed in Example 16 above, at aloading of 20%. This loaded epoxy was applied to the ends of tubing madeaccording to Example 8 of U.S. patent application Ser. No. 08/103,328cited above, and these ends were inserted into a Y-sites fabricated fromABS polymer. Care was taken to keep the thickness of the epoxy mixtureon the tubing uniform. These constructions were placed in the coil ofthe LEPEL induction heater described above in Example 24, and the heaterwas energized for 25 seconds. This heated the epoxy/coated fiber mixtureenough to cure it slightly. The green strength in these treated sampleswas greater than control samples made without the use of susceptorparticles.

                                      TABLE 1                                     __________________________________________________________________________    EXAMPLE #                                                                            1             2             3             4                            LAYER  OUTER                                                                              CORE                                                                              INNER                                                                              OUTER                                                                              CORE                                                                              INNER                                                                              OUTER                                                                              CORE                                                                              INNER                                                                              OUTER                                                                              CORE                                                                              INNER                      E.O. EVA      E.O. EVA      E.O. EVA      E.O. EVA                            (ATTANE                                                                            (28%                                                                              SURLYN                                                                             (ATTANE                                                                            (28%                                                                              SURLYN                                                                             (ATTANE                                                                            (28%                                                                              SURLYN                                                                             (ATTANE                                                                            (28%                                                                              SURLYN              MATERIAL                                                                             4602)                                                                              VA) 1702 4602)                                                                              VA) AD-8255                                                                            4602)                                                                              VA) AD-8255                                                                            4602)                                                                              VA) 8320                       EXTRUDER BARREL                                                        __________________________________________________________________________    ZONE 1 TEMP                                                                          121  121 35   121  121 135  121  121 121  121  121 121                 ° C.                                                                   ZONE 2 TEMP                                                                          149  157 163  149  151 163  149  157 149  157  157 157                 ZONE 3 TEMP                                                                          176.5                                                                              176.5                                                                             176.5                                                                              176.5                                                                              176.5                                                                             176.5                                                                              176.5                                                                              176.5                                                                             176.5                                                                              176.5                                                                              176.5                                                                             176.5               ZONE 4 TEMP                                                                          176.5                                                                              179.5                                                                             176.5                                                                              176.5                                                                              179.5                                                                             176.5                                                                              176.5                                                                              179.5                                                                             176.5                                                                              196  196 196                 ZONE 5 TEMP 182           182      176.5                                                                              182 176.5                                                                              196  196 196                                                    (gate)                                                                             (gate)                                                                            (gate)                                                                             (gate)                                                                             (gate)                                                                            (gate)              CAST ROLL   12°    12°                                          TEMP                                                                          SCREW RPM                                                                            3.2      3.7  3.2      3.6                                             LINE SPEED  0.85          0.85                                                            M/MIN         M/MIN                                               MODULUS     26.9                                                                              117.0     26.9                                                                              71.0      26.9                                                                              71.0      26.9                    (LAYER)                                                                       (MPa)                                                                         STRESS AT   3.5 7.0       3.5 6.1       3.5 6.1       3.5                     50% STRAIN                                                                    (LAYER)                                                                       (MPa)                                                                         MODULUS                                                                              42.7          36.0          36.0          27.0                         (COMPOSITE)                                                                   (MPa)                                                                         STRESS AT                                                                            4.1           3.8           3.8           3.8                          50% STRAIN                                                                    (COMPOSITE)                                                                   (MPa)                                                                         __________________________________________________________________________    EXAMPLE #                                                                              5                          6                                         LAYER    OUTER                                                                              CORE  CENTER                                                                             CORE  INNER                                                                              OUTER                                                                              CORE  CENTER                                                                             CORE  INNER                        E.O.       E.O.            E.O.       E.O.                                    (ATTANE                                                                            EVA   (ATTANE                                                                            EVA   SURLYN                                                                             (ATTANE                                                                            EVA   (ATTANE                                                                            EVA   SURLYN              MATERIAL 4602)                                                                              (28% VA)                                                                            4602)                                                                              (28% VA)                                                                            8320 4601)                                                                              (28% VA)                                                                            (4601)                                                                             (28%                                                                                8320)                        EXTRUDER BARREL                                                      __________________________________________________________________________    ZONE 1 TEMP ° C.                                                                121  121   121  121   121  121  121   121  121   121                 ZONE 2 TEMP                                                                            157  157   157  157   157  157  157   157  157   157                 ZONE 3 TEMP                                                                            176.5                                                                              176.5 176.5                                                                              176.5 176.5                                                                              176.5                                                                              176.5 176.5                                                                              176.5 176.5               ZONE 4 TEMP                                                                            196  196   196  196   196  196  196   196  196   196                 ZONE 5 TEMP                                                                            196  196   196  196   196  196  196   196  196   196                                     (gate)                     (gate)                         CAST ROLL TEMP                                                                              R.T.       R.T.            R.T.       R.T.                      SCREW RPM                                                                     LINE SPEED          1.8                        0.82                                               M/MIN                      M/MIN                          MODULUS       26.9       26.9            26.9       26.9                      (LAYER) (MPa)                                                                 STRESS AT 50% 3.5        3.5             3.5        3.5                       STRAIN                                                                        (LAYER) (MPa)                                                                 MODULUS  37.8                       33.1                                      (COMPOSITE)                                                                   (MPa)                                                                         STRESS AT 50%                                                                          4.2                        4.2                                       STRAIN                                                                        (COMPOSITE)                                                                   (MPa)                                                                         __________________________________________________________________________    EXAMPLE # 7                        8    9    10  11  12                       LAYER     OUTER                                                                              CORE CENTER                                                                             CORE INNER                  OUTER                                                                              CORE                          E.O. E.B. E.O. E.B.           E.B.         E.O. E.B.                          (ATTANE                                                                            (EXACT                                                                             (ATTANE                                                                            (EXACT                                                                             SURLYN                                                                             EVA  (EXACT                                                                             EMAC                                                                              EMAC                                                                              (ATTANE                                                                            (EXACT              MATERIAL  4602)                                                                              4028)                                                                              4602 4028 8320 (28% VA)                                                                           4024)                                                                              (2205)                                                                            (2260)                                                                            4602)                                                                              4024)                         EXTRUDER BARREL                                                     __________________________________________________________________________    ZONE 1 TEMP ° C.                                                                 121  121  121  121  121  121  129  121 121.5                                                                             121  129.5               ZONE 2 TEMP                                                                             157  157  157  157  157  157  176.5                                                                              158.5                                                                             159.5                                                                             149  176.5               ZONE 3 TEMP                                                                             176.5                                                                              176.5                                                                              176.5                                                                              176.5                                                                              176.5                                                                              176.5                                                                              190.5                                                                              180 180.5                                                                             176.5                                                                              190.5               ZONE 4 TEMP                                                                             196  196  196  196  196  179.5                                                                              193  194 193 176.5                                                                              193                 ZONE 5 TEMP                                                                             196  196  196  196  196  182       193 193                                              (gate)         (gate)                                     CAST ROLL TEMP R.T.      R.T.      10        10                               SCREW RPM                               210  206 205 5.9  210                 LINE SPEED          0.82           0.76      0.79                                                                              1.1                                              M/MIN                                                     MODULUS (LAYER)                    26.9 29.4 33.4                                                                              47.8                                                                              29.4                     (MPa)                                                                         STRESS AT 50%                      3.5  3.8  4.0 4.5 3.8                      STRAIN                                                                        (LAYER) (MPa)                                                                 MODULUS   31.5                                       34.0                     (COMPOSITE)                                                                   (MPa)                                                                         STRESS AT 50%                                                                           3.7                                        3.9                      STRAIN (MPa)                                                                  (COMPOSITE)                                                                   __________________________________________________________________________    EXAMPLE #                                                                              13       14            15             18                             LAYER    CORE                                                                              INNER                                                                              OUTER                                                                             CORE INNER                                                                              OUTER                                                                              CORE                                                           75% EVA                      70% EMAC                                         (28% VA)  E.O.               2205                                EMAC                                                                              SURLYN                                                                             EMAC                                                                              25% EVA                                                                            SURLYN                                                                             (ATTANE                                                                            EMAC                                                                              SURLYN                                                                              EMAC                                                                              30% SURLYN                                                                           SURLYN              MATERIAL 2205                                                                              8320 2205                                                                              (19% VA)                                                                           8320 4602)                                                                              2205                                                                              (AD-8255)                                                                           2205                                                                              8320   8320                         EXTRUDER BARREL                                                      __________________________________________________________________________    ZONE 1 TEMP                                                                            121 121  160 140  160  121  121 135   160 140    160                 ZONE 2 TEMP                                                                            157 157  185 175  185  149  157 163   185 175    185                 ZONE 3 TEMP                                                                            176.5                                                                             176.5                                                                              185 185  185  176.5                                                                              176.5                                                                             176.5 185 185    185                 ZONE 4 TEMP                                                                            196 196  --  185  --   176.5                                                                              179.5                                                                             176.5 --  185    --                  ZONE 5 TEMP                                                                            196 196  185 185  185       182       185 185    185                                   (gate)                                                                            (gate)                   (gate)                                                                            (gate)                     CAST ROLL TEMP                                                                         R.T.         R.T.           12°    R.T.                       SCREW RPM                       3.2      3.7                                  LINE SPEED                                                                             0.91         0.91           0.85          0.91                                M/MIN        M/MIN          M/MIN         M/MIN                      MODULUS  33.4                        26.9                                                                              117.0                                (LAYER) (MPa)                                                                 STRESS AT 50%                                                                          4.0                         3.5 7.0                                  STRAIN                                                                        (LAYER) (MPa)                                                                 MODULUS (MPa)                   42.7                                          (COMPOSITE)                                                                   STRESS AT 50%                   4.1                                           STRAIN (MPa)                                                                  (COMPOSITE)                                                                   __________________________________________________________________________    EXAMPLE #            19            20                                         LAYER              OUTER    INNER  OUTER    CORE    INNER                     MATERIAL           EMAC 2205                                                                              SURLYN 8320                                                                          EMAC 2205                                                                              EVA (28% VA)                                                                          SURLYN 8320                                  EXTRUDER BARREL                                            __________________________________________________________________________    ZONE 1 TEMP        160      160    160      140     160                       ZONE 2 TEMP        185      185    185      175     185                       ZONE 3 TEMP        185      185    185      185     185                       ZONE 4 TEMP        --       --     --       185     --                        ZONE 5 TEMP        185      185    185      185     185                                          (gate)          (gate)   (gate)                            CAST ROLL TEMP                              R.T.                              SCREW RPM                                                                     LINE SPEED         0.91                     0.91                                                 M/MIN                    M/MIN                             MODULUS (LAYER)                                                               STRESS AT 50% STRAIN (LAYER)                                                  MODULUS (COMPOSITE)                                                           STRESS AT 50% STRAIN (COMPOSITE)                                              __________________________________________________________________________    EXAMPLE # 35                               36                                 LAYER     OUTER   CORE  CENTER  CORE  INNER                                                                              OUTER    CORE INNER                          E.O.    EVA   E.O.    EVA   SURLYN                                                                             E.O.     EMAC SURLYN               MATERIAL  (ATTANE 4602)                                                                         (28% VA)                                                                            (ATTANE 4602)                                                                         (28% VA)                                                                            9320 (ATTANE 4601)                                                                          2260 AD-8255                        EXTRUDER BARREL                                                     __________________________________________________________________________    ZONE 1 TEMP ° C.                                                                 121     121   121     121   121  160      140  160                  ZONE 2 TEMP                                                                             157     157   157     157   157  185      175  185                  ZONE 3 TEMP                                                                             176.5   176.5 176.5   176.5 176.5                                                                              185      185  185                  ZONE 4 TEMP                                                                             196     196   196     196   196  --       185  --                   ZONE 5 TEMP                                                                             196     196   196     196   196  185      185  185                                          (gate)             (gate)   (gate)                    CAST ROLL TEMP    R.T.          R.T.                R.T.                      SCREW RPM                                                                     LINE SPEED              1.8                         0.91                                              M/MIN                       M/MIN                     MODULUS           26.9          26.9                                          (LAYER) (MPa)                                                                 STRESS AT 50%     3.5           3.5                                           STRAIN                                                                        (LAYER) (MPa)                                                                 MODULUS                                                                       (COMPOSITE)                                                                   (MPa)                                                                         STRESS AT 50%                                                                 STRAIN                                                                        (COMPOSITE)                                                                   (MPa)                                                                         __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    for Example 1                                                                          Time to reach   Degree of chamber                                                                      Degree of seat                              Temperature (° C.)                                                              temperature (min)                                                                     Pressure (kg/cm.sup.2)                                                                formation                                                                              formation                                   __________________________________________________________________________     93      18      0.21    partial  partial                                      96      25      0.21    partial  partial                                      97      13      0.21    partial  partial                                     106      16      0.21 to 0.27                                                                          complete complete                                    106      16      0.42    complete complete                                    116      25      0.21 to 0.24                                                                          complete chamber formed,                                                               but collapsed                               __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________    for Example 2                                                                          Time to reach   Degree of chamber                                                                      Degree of seat                              Temperature (° C.)                                                              temperature (min)                                                                     Pressure (kg/cm.sup.2)                                                                formation                                                                              formation                                   __________________________________________________________________________     93      18      0.21                                                          96      25      0.21                                                          97      13      0.21    partial  partial                                     106      16      0.21    partial  partial                                     106      25      0.24    complete complete                                    116       4      0.21    complete complete                                    __________________________________________________________________________

                  TABLE 4                                                         ______________________________________                                        for Example 5                                                                 Cassette forming                                                              conditions                                                                                          Condition Condition                                     Process Attribute     set #1    set #2                                        ______________________________________                                        Starting temperature (° C.)                                                                  38        49                                            Formation (highest) temperature (° C.)                                                       91.7      91.1                                          Low air pressure (kg/cm.sup.2)                                                                      0.14      0.21                                          Plate temperature where low air pressure was                                                        40.6      51.7                                          initiated (° C.)                                                       High air pressure (kg/cm.sup.2)                                                                     0.91      0.91                                          Plate temperature where high air pressure was                                                       7300      57                                            initiated (° C.)                                                       Hydraulic ram pressure (kg)                                                                         4:56      4:22                                          Cycle time (min)      >77       >77                                           Seal temperature range (° C.)                                                                >88       >88                                           Formation Temperature Range (° C.)                                                           >88       >88                                           Seal strength (kg)    4.5       4.5                                           ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        for Example 5                                                                 Volumetrics test on complete                                                  cassettes                                                                             Volume delivered during                                                                      Volume delivered                                               regular pumping                                                                              during "KVO" pumping (in                               Condition set                                                                         (40 ml expected)                                                                             ml/hour, 1.0 ml/hr expected)                           ______________________________________                                        1       40.9           1.1                                                    1       42.7           2.2                                                    1       42.8           5.9                                                    1       44.0           11.1                                                   1       40.2           3.0                                                    2       41.5           1.4                                                    2       43.0           3.0                                                    2       42.9           8.2                                                    2       41.8           4.7                                                    2       44.0           2.7                                                    2       45.7           1.1                                                    2       42.9           1.8                                                    2       39.8           not done                                               ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        for Example 9                                                                 Formation                                                                     Temperature (° C.)                                                                Pressure (kg/cm.sup.2)                                                                     Degree of Chamber formation                           ______________________________________                                        74         0.42         Partial (Dome)                                        80.5       0.42         Complete (thin walls)                                 88         0.42         Chamber collapsed                                     ______________________________________                                    

                  TABLE 7                                                         ______________________________________                                        for Example 9                                                                 Temperature of top                                                                       Temperature of bottom                                                                       Degree of Chamber                                    plate (° C.)                                                                      plate (° C.)                                                                         formation                                            ______________________________________                                        75         75            Partial                                              79.5       83                                                                 80.5       84            Complete, but with thin                                                       walls in some chambers                               ______________________________________                                    

While a description of the preferred weight fractions, processingconditions, and product usages have been provided by the examples, thescope of the invention is not to be limited thereto or thereby. Variousmodifications and alterations of the present invention will be apparentto those skilled in the art without departing from the scope and spiritof the present invention. The examples described in this application areillustrative of the possibilities of varying the amounts and types ofpolymeric materials in the multilayered tubings and films to achievecharacteristics for specific purposes.

Consequently, for an understanding of the scope of the presentinvention, reference is made to the following claims.

We claim:
 1. A bonding interlayer for joining flexible thermoplastictubing with a molded thermoplastic fluid transporting component, thebonding interlayer comprising a mixture of an adhesive polymer materialand a sufficient amount of susceptor particles to cause localizedheating of the mixture and adjacent surfaces of the flexiblethermoplastic tubing and the molded thermoplastic fluid transportingcomponent when the mixture is exposed to electromagnetic radiation, sothat a leak-free joint is formed by heat sealing between the flexiblethermoplastic tubing and the molded thermoplastic fluid transportingcomponent.
 2. The bonding interlayer of claim 1, wherein the adhesivepolymer material is a thermoset adhesive.
 3. The bonding interlayer ofclaim 1, wherein the susceptor particles are selected from the groupconsisting of particles coated with magnetic material, particles coatedwith conductive material, and ferromagnetic amorphous powders.
 4. Thebonding interlayer of claim 1, wherein the amount of susceptor particlesin the mixture is between about 1% and about 65% of total volume of themixture.
 5. The bonding interlayer of claim 4, wherein the amount ofsusceptor particles in the mixture is between about 1% and about 30% oftotal volume of the mixture.
 6. The bonding interlayer of claim 1,wherein the molded thermoplastic fluid transporting component isselected from the group consisting of cassettes, drip chambers, and luerlocks.
 7. The bonding interlayer of claim 1, wherein the flexiblethermoplastic tubing and the molded thermoplastic fluid transportingcomponent are made from chlorine-free materials.
 8. The bondinginterlayer of claim 1, wherein the flexible thermoplastic tubing is amultilayered tube.
 9. The bonding interlayer of claim 1, wherein themolded thermoplastic fluid transporting component comprises amultilayered plastic film.
 10. The bonding interlayer of claim 9,wherein the multilayered plastic film comprises:a) a core layer of atleast one chorine-free first thermoplastic polymer having a Young'smodulus within a range of about 10 to about 60 megaPascals; b) anoutside surface layer of at least one chlorine-free second thermoplasticpolymer having a Young's modulus up to about ten times the Young'smodulus of the core layer thermoplastic polymer and being capable ofnon-stick release from a heated surface; and c) an inside surface layerof at least one chlorine-free third thermoplastic polymer having aYoung's modulus up to about ten times the Young's modulus of the corelayer thermoplastic polymer and being capable of heat self-sealing. 11.The bonding interlayer of claim 10, wherein the second and thirdthermoplastic polymers have Young's moduli within a range of from about15 to 300 megaPascals.